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By George B. Langford

The McIntyre mine is in the Pearl Lake section of the Porcupine gold area. The rocks are Keewatin lavas intruded by quartz porphyries and albitite dies of Algoman age. Gold-bearing quartz veins are found in the Keewatin rocks near the porphyry stocks. The whole area has been highly compressed by forces acting along a N. 20°W. line. These forces folded the Keewatin rocks before the intrusion of the Algoman rocks, and later schisted both the Keewatin and Algoman rocks. Vein fractures were developed after the folding but before the development of the schist by the compres-sive forces being locally broken up into couples. These couples were set up by the differential resistance to deformation of porphyries and basalts, and also by the competency of the dacites and incompetency of the tuffs and fragmental rocks. During the important period of vein formation, two zones were developed—an inner productive zone in which the quartz veins are ankerite-bearing and an outer barren zone in which the quartz veins are calcite-bearing. The vein solutions originated in the same magrna that supplied the albitite dikes. Introduction The McIntyre mine, in the Porcupine gold area of northern Ontario, has passed its twenty-sixth birthday and has been producing gold since early in 1912. During this time approximately ten million tons of ore has been mined and over three and a half million ounces of gold recovered. This amount of ore would be sufficient to fill 2300 standard railway freight trains, each of 100 cars, and the gold produced, although only equivalent to a cube 51/2 ft. to the side, would weigh approximately 100 tons, a load for three freight cars. Silver has been produced in the ratio of 1 oz. of silver to every 4.4 oz. of gold, so that the total silver recovery is in the neighborhood of 700,000 ounces. The early history of the mine, like that of many others, shows that for several years it fought an uphill struggle for existence. One of the important features in winning this fight was the early recognition of some of the geological conditions responsible for the ore deposits, and the application of this knowledge in the search for ore and in the acquiring of adjoining properties. As early as 1913—only two years after the mine was opened—a geological department was organiaed. It has functioned almost continuously since that date and has demonstrated the importance

Jan 1, 1941

By George B. Langford

The McIntyre mine is in the Pearl Lake section of the Porcupine gold area. The rocks are Keewatin lavas intruded by quartz porphyries and albitite dies of Algoman age. Gold-bearing quartz veins are found in the Keewatin rocks near the porphyry stocks. The whole area has been highly compressed by forces acting along a N. 20°W. line. These forces folded the Keewatin rocks before the intrusion of the Algoman rocks, and later schisted both the Keewatin and Algoman rocks. Vein fractures were developed after the folding but before the development of the schist by the compres-sive forces being locally broken up into couples. These couples were set up by the differential resistance to deformation of porphyries and basalts, and also by the competency of the dacites and incompetency of the tuffs and fragmental rocks. During the important period of vein formation, two zones were developed—an inner productive zone in which the quartz veins are ankerite-bearing and an outer barren zone in which the quartz veins are calcite-bearing. The vein solutions originated in the same magrna that supplied the albitite dikes. Introduction The McIntyre mine, in the Porcupine gold area of northern Ontario, has passed its twenty-sixth birthday and has been producing gold since early in 1912. During this time approximately ten million tons of ore has been mined and over three and a half million ounces of gold recovered. This amount of ore would be sufficient to fill 2300 standard railway freight trains, each of 100 cars, and the gold produced, although only equivalent to a cube 51/2 ft. to the side, would weigh approximately 100 tons, a load for three freight cars. Silver has been produced in the ratio of 1 oz. of silver to every 4.4 oz. of gold, so that the total silver recovery is in the neighborhood of 700,000 ounces. The early history of the mine, like that of many others, shows that for several years it fought an uphill struggle for existence. One of the important features in winning this fight was the early recognition of some of the geological conditions responsible for the ore deposits, and the application of this knowledge in the search for ore and in the acquiring of adjoining properties. As early as 1913—only two years after the mine was opened—a geological department was organiaed. It has functioned almost continuously since that date and has demonstrated the importance

Jan 1, 1941

By R. A. Burmeister, P. E. Greene

Two methods for the synthesis and growth of single crystals of B6 P are described: a solution-growth process employing nickel as the solvent, and a vapor-growth process employing BBr3 and pH3 as the reac-tants. Relevant portions of the Ni-B-P phase diagram have been examined and liquidus data are presented for an isobaric section at an equivalent P2 pressure of 3.8 Torr, and an isothertnal section at 1300°C. Solution-growth techniques are described and the purity and crystalline perfection of the resulting material is discussed. Epitaxial growth of BeP on &P substrates has been obtained using the vapor-phase system. Evidence is presented which supports the assignment of the stoichioknetry B6P to boron sub-plwsphide. THE B-P system differs from other III-V systems in that it contains two distinct compounds. The existence of the monophosphide (BP) has been known for some time,' whereas the subphosphide (B6P) was reported only recently.' Both of these compounds are large bandgap semiconductors (Eg = 2.0 ev for BP~ and 3.3 ev for B6P4), and are therefore of interest for optoelectronic applications. The crystal structure of B6P is quite different from those of most semiconductors, being derived from that of a-rhombohedral boron by the incorporation of the two phosphorus atoms in the intericosahedral sites of the a-boron unit cell?76 B6P also exhibits a number of unusual characteristics, including a high degree of chemical inertness, hardness, and high-temperature stability. No information concerning other physical properties is available in the literature. The present study is part of a broader investigation of the preparation and properties of B6P. This paper considers methods of growing single crystals of B6P of suitable size and quality for physical-property measurements. A detailed discussion of the electrical and optical properties of B6P will be given elsewhere.' GENERAL CONSIDERATIONS The method first used to synthesize B6P was the disproportionation of BP' according to the reaction The equilibrium P2 pressures corresponding to this reaction were also determined .'" It is therefore possible, in principle, to apply several of the reactions reported for the synthesis of BP to the synthesis of B6P merely by selecting lower phosphorus pressures or higher temperatures, in accordance with the equilibrium data. Other techniques for the direct synthesis of microcry stalline B8P have also been reported.1°

Jan 1, 1968

By Joe O. Ledbetter

INTRODUCTION Health physics as a profession really got a significant start during the Manhattan Project of World War 11. The Health Physics Society has recently published its 25th anniversary issue of the journal (June 1980). There was concern over radiation exposures during and after uranium production, especially about radium and its daughter products [Jackson 19401 and, as evidenced by the frequency of articles in the literature, there still is. The reason for this concern was expressed by Harley as "Workers engaged in the mining and pro- cessing of radium-bearing materials are exposed to dusts of the parent, to radon, and to the radon daughter products. In- haled radioactive particulates may be retained in the lung or redistributed to other organs of the body. Relatively minute de- posits of radioactive substances, particularly alpha emitters, have been clearly shown to be the etiological factor in a variety of injuries to industrial and re- search workers. " [Harley 1953] Emphasis in measurements has been placed on radium in water and radon in air, since these are the principal mobilized phases; however, it should be kept in mind that radium-containing particles do become suspended in air as aerosols and radon absorbs in liquids. Much of the uranium mining and production is being carried out aboveground. The principal difference between underground and surface (pit or leach) mining of uranium is the reversal in the relative importance of roles for the types of radiation dose. For aboveground the major radiation exposure is external gamma ray, whereas for underground it is internal alpha; for aboveground, the whole body penetrating is of greater importance than the lung alpha dose. AS a result of the politics involved and the law- suits for any and all diseases as being occupationally- caused, today , more than ever before, the successful performance of the activities connected with uranium production--before-, during-, and after-the-fact-- must include the provision of first class radiation protection. Such protection can be achieved by good measurements, thorough risk evaluations, and adequate controls. Meeting the ALARA (As Low As Reasonably Achievable) philosophy necessarily entails the determination of what is reasonable exposure. The necessary and sufficient elements of radiation safety under the ALARA dictum require a hard look at the dose versus effects data. There are times when the health physicist needs to make decisions of judgement rather than compliance with a well-defined regulation value. In order to facilitate such decisions, the real world must be separated from opinions that are merely artifacts of statistical variation and from the unprovable "what ifs" that are slanted to question the morality of any non-Luddite. UNITS VOCABULARY FOR DOSIMETRY There have been many radiation quantifying and dosimetric units introduced in the past. Fortunately, most of them did not catch on enough to become required knowledge for reading the health physics literature. The unit definitions necessary for our purposes here are the following: -curie (Ci)--unit of radioactivity equal to 3.7 x 10 10 disintegrations per second Webster&apos;s 19711 or the quantity of radionuclide that undergoes 3.7 x 10 nuclear transformations per second. Environmental levels of radioactivity are usually measured in picocuries (10-l2 Ci) per cubic meter for air and in picocuries per liter (pCi/~) for water and sometimes for air. .roentgen (R)--exposure dose of x or gamma rays that gives 1 esu of charge (either sign) to 1 cc of dry air @ STP. The roentgen is equivalent to an energy absorption of 86.7 ergs/g of air [Gloyna and Ledbetter 19691. .rad--radiation absorbed dose of 100 ergs per gram of absorber. The SI unit for absorbed radiation dose is the Gray; 1 Gy = 100 rads. orem--radiation absorbed dose of 1 rad times the quality factor (QF) for that radiation. The QF is 1 for x rays, gamma rays, beta rays, and posi- trons. For heavy ionizing particulate radiation, QF is a function of the amount of energy trans- ferred per unit length of travel, i.e. , the linear energy transfer (LET); the values of QF:LET in keV/um are as follows: 1:<3.5; 1-2:3.5-7; 2-5:7-23; 5-10:23-53; and 10-20:53-175 [Morgan and Turner 19 671 . For radiobiology, relative biological effectiveness (RBE) is recommended for use instead of the quality factor above that is for radiation protection: the RBE is the ratio of the dose of 200 kVp x rays to the dose of radia- tion in question (both in rads) to cause the same

Jan 1, 1980

By Eckley B. Coxe

Having been appointed, on February 19th, 1890, a member of the Commission created by the Legislature of Pennsylvania for the purpose of investigating the " Waste of Coal Mining, with the View to the Utilizing of the Waste" (waste in this case referring specially to the small sizes of anthracite heretofore thrown away), my attention was naturally directed to the mash economical method of burning these small sizes.* Although I had been Familiar with the burning of anthracite for • many years, I found when I came to study the matter carefully that I was far from thoroughly understanding it, particularly with reference to the hurning of the smaller sizes, and that the literature of the subject, which was not very extensive, had more of a tendency to confuse than to enlighten me. I began therefore to investigate the subject so as to arrive if possible at some definite principles applicable to the question. With the aid of my assistant, Mr. John R. Wagner, I began at Drifton a series of experiments upon the burning of small anthracites. We first erected a small furnace with a grate 3 feet long and 2 feet wide, with which we experimented about two months. From the information thus acquired, we designed and built another furnace of about the same size, which gave us facilities for extending our investigations still further. After experimenting several months with the second furnace, we built a third one, which was much larger, having a grate area of about 68 square feet, which was exactly the size of the grate used in the boiler-plants of&apos; Coxe Bros. &

Jan 1, 1894

By J. Lohrenz, C. R. Clark, B. G. Bray

Procedures to calculate the viscosities of in situ reservoir gases and liquids from their composition have been developed and evaluated. Given a composition expressed in methane through heptanes-plus, hydrogen sulfide, nitrogen and carbon dioxide together with the molecular weight and specific gravity of the heptanes-plus fraction, the procedures are capable of calculating the viscosity of the gas or liquid at the desired temperature and pressure. The procedure for reservoir liquids was developed using the residual viscosity concept and the theory of corresponding states, and was evaluated by comparing experimental and calculated results for 260 different reservoir oils ranging from black to highly volatile. The average absolute deviation was 16 per cent. This is the first known procedure for calculating the viscosity of reservoir liquids from their compositions as normally available, i.e., including the heptanes-plus fraction. The procedure for reservoir gases uses a sequence of previously published correlations. Evaluation of the procedure was accomplished by comparison of 300 calculated and experimental viscosities for high-pressure gar mixtures in the literature. The average absolute deviation was 4 per cent. The calculations are useful for (I) determining viscosities in compositional material balance computations and (2) predicting the viscosity decrease which occurs when gases, LPG, or carbon dioxide dissolve in reservoir oils. INTRODUCTION Methods to predict viscosities of reservoir fluids from the normally available field-measured variables have been presented. Beal,1 Standing,2 and Chew and Connally3 orrelated oil viscosities with temperature, pressure, oil gravity and gas-oil ratio. Carr, Kobayashi, and Burrows4 and Katz et al.5 have presented correlations for reservoir gas viscosities as a function of temperature, pressure and gas gravity. Lie all intensive physical properties, viscosity is completely described by the following function: Eq. 1 simply states that viscosity is a function of pressure, temperature and composition. These previous correlations1- hay be viewed as modifications of Eq. 1, wherein one assumes more simple functions may be used. The assumptions are practical, because the composition is frequently not known. Further, the assumptions are sufficiently valid so that these correlations are frequently used for reservoir engineering computations. In compositional material balance"&apos; computations, the compositions of the reservoir gases and oils are known. The calculation of the viscosities of these fluids using this composition information is required for a true and complete compositional material balance. For reservoir gases, Carr, Kobayashi and Burrows4 have presented a suitable compositional correlation. For reservoir oils, no correlation is available, and data from reservoir fluid analyses have been used7-9 for compositional material balance calculations.* From a theoretical point of view, this is entirely invalid. The reservoir fluid analysis, whether flash, differential, or other process, does not duplicate the compositions which occur during the actual reservoir depletion process, therefore the viscosities measured during reservoir fluid analysis are not those which occur in the reservoir. From a practical point of view, the "error" of using viscosities from reservoir fluid analysis is of varying and unknown significance. One can say qualitatively that the error is greatest where compositional effects are greatest, i.e., for volatile oil and gas condensate reservoirs and pressure maintenance operations. The first requirement to obtain a quantitative estimate of the significance of the error is to develop a reliable compositional correlation for the viscmities of reservoir oils. No such correlation has been available. Consistent with this requirement, the objective of this study was to develop a procedure to predict the viscosity of reservoir fluids from their compositions. Normally, the compositions of reservoir fluids are available expressed as mole fractions of hydrogen sulfide, nitrogen, carbon dioxide and the hydrocarbons methane through the heptane-plus fraction, with the average molecular weight and specific gravity of the latter. The final correlation was to use the composition in this form. While the more challenging objective of the study was the development of a correlation for the viscosities of reservoir oils, the viscosities of reservoir gases were also studied. The end result of the study was a procedure to calculate the viscosities of reservoir gases and liquids suitable

Jan 1, 1965

By Frank M. Randall

The Buick mill is located at the site of the old Buick general store, approximately 4 miles south of Bixby, Missouri on route KK. It is a part of the operations in the area now called the "New Lead Belt". The ore body lies at an elevation of 270 feet above sea level, and is fairly flat lying, becoming slightly deeper toward the south. The mineralization is due to the secondary deposition of galena, sphalerite, chalcopyrite, pyrite, calcite, dolomite and some localized drusy quartz in a country rock of dolomitic limestone. The galena is fairly coarse grained with some large crystaline structure, and some oxidized surfaces. The sphalerite is fine grained- small crystals containing Cd (about 0.7%) and Ag (about 10 oz per ton) in solid solution. The chalcopyrite is fine grained, fine crystals that are sometimes massive in nature. The mine plan is a modified room and pillar system. Broken ore at the mine face will be transported to several different ore passes by rubber tired load-haul-dump units. Ore passes will drop the ore to a rail haulage level some 90 feet below the mining level where bottom dump cars will deliver it to a 42 in. Nordberg gyratory crusher. Two 12 ton capacity skips in balance carry the ore some 1,200 feet to the surface. The hoist is equipped with automatic controls for loading, hoisting and unloading.

Jan 1, 1970

By Paul Merica

ALTHOUGH nickel was discovered and isolated as early as 1750 and its valuable properties recognized, many years passed before it was used commercially for wire, sheet, rods, etc., in the pure form. This was due partly to its high cost at that time and partly to the fact that it was not possible to refine and cast nickel into ingots sufficiently malleable to be amenable to the usual forging, rolling, or drawing processes. So remarkable was this fact, and so different from the experience at that time with metals such as copper and iron, that it has left its impress on the no-menclature within the nickel industry. To this day, furnace-cast nickel produced in such a manner as to be suitable for rolling and forging is called malleable nickel to distinguish it from the ordinary pig and shot nickel of commerce. In 1878, the firm of Jos. Wharton, of Philadelphia (which later became The American Nickel Works, a constituent of The International Nickel Co.) exhibited at the Paris Exhibition specimens of rolled pure nickel strip and of drawn nickel wire. About this time, there was considerable activity in the study of the refining of nickel and several methods were described, some of which were patented, for the production of furnace-cast malleable nickel including the use of manganese (Boed-dicker,1 Selve and Lotter2), the use of potassium permanganate (Bernsdorfer Metallwarenfabrik3) and the use of phosphorus (Garnier4). By far the most efficient method was discovered by Th. Fleitmann in 1879;5 it consisted in adding to the molten nickel, just before pouring the castings, from 0.05 to 0.125 per cent. of metallic magnesium. This soon became the recognized final malleableizing treatment for furnace-cast nickel.

Jan 1, 1925

By J. Ruzicka

In creep testing, material is subjected to a constant load, preferably at a constant temperature, and its rate of deformation is measured. The method of loading can be of various types but in this paper only creep testing under tensile load will be considered. The ordinary tensile test is essentially a comparison test in conditions that frequently hear little or no relation to those under which the test material is to be used in service. The purpose of creep tests is to measure the strength of the test material at slow rates of deformation that more nearly approach the rates realized in service. One purpose of this paper is to illustrate that the creep test, in addition to its value as a service test, is superior to the ordinary tensile test as a sensitive tool for the comparison of certain metals in investigative testing. The other purpose is to describe equipment having distinctive features of design that make it especially suitable for such tests. Representative data obtained with this equipment on a group of rolled zinc-base materials are given. These data are compared with those from practical comparison tests of the creep type on weatherstrip fabricated from the same group of materials. The comparison illustrates the value of the fast creep test and of the equipment. The Equipment The creep equipment consists essentially of a tank containing a constant-temperature oil bath in which the creep of 14 specimens, loaded by means of levers, is measured by means of one movable extensometer. Figs. 1, 2 and 3 illustrate its general construction and appearance. Constant-temperalure Oil Balh.—A common constant-temperature bath requiring only one temperature-controlling equipment for a number of specimens was chosen as the best means of fulfilling the requirements of low cost and compactness. In addition, this allows the testing of a group of specimens under identical temperature conditions.

Jan 1, 1937

By Reynold Q. Shotts

INTRODUCTION THE small domestic underfeed stoker as now designed is unusually sensitive to the coking and plastic properties of coals, and when the attempt is made to burn the high rank coking and caking coals of the Appalachian fields, serious trouble may occur. Part of the trouble may be caused by the ash content and clinkering characteristics of the particular coal in use, but more often it is the result of an excessive accumulation of coke in the form of "trees" or masses in the fuel bed. Often the zone of burning becomes so restricted that the fire goes out, and in extreme cases the fire may be lifted completely out of the fuel bed and away from the air ports. Even if the fire is preserved, excessive coking may cause response to subsequent heat demand to be slow and irregular. Coke trees seem to grow. most readily during periods of hold-fire operation, so that in order to preserve the fire in mild weather it is often necessary to set the timer for such a long operating period each hour that much unneeded and unwanted heat is developed, causing discomfort. During demand periods the fire may pick up so slowly that the intense burning which develops just before stoker cut-off causes a serious overshooting of the thermostat. Stoker coal performance tests which have been made in a number of laboratories 1, 2, 3, 4, 5 are one method of approach to the problem of selecting stoker coals. As yet these tests have not been standardized and they are expensive and time-consuming. The value of the results probably increases with the length of the test. Sherman and co-workers at Battelle Memorial Institute believe that even a one-week test is not too reliable a trial2 and it is quite likely that others will agree. A great advantage of such tests is that characteristics of coals, other than the tendency to form coke masses, may be evaluated from them. The selection of stoker coals would be greatly facilitated if there existed some simple measure of the tendency of a coal to form coke in a fuel bed. Although possessing all of the disadvantages of any small-scale laboratory test, the test for the free-swelling index of coal has been found useful for evaluating the probable effects of swelling properties upon combustion. 7 Ostborg, Limbacher and Sherman, have shown that the test can predict, roughly, the tendency of coke to accumulate in the fuel bed of a domestic stoker. They also gave instances of its value in predicting combustion behavior in some large installations. The use of the test for free-swelling index has become well established and has been adopted as a standard by the American Society for Testing Materials.8 When domestic stoker coal investigations began at the State Mine Experiment Station in the summer of 1944, it was decided

Jan 1, 1948

By R. L. Ash, R. R. Rollins, C. J. Konya

An investigation was performed to determine conditions for optimizing the spacing of simultaneously initiated multiple explosive columns. This was done by using models of mortar, dolomite, and Plexiglas with 10-grain mild detonating fuse as the explosive charge. It was desired to simulate blastholes with multiple primers initiated by detonating fuse or when high-velocity explosives are used in low-velocity materials. It was found that optimum spacing between multiple charges was strongly influenced by charge length. At less than optimum charge length, the spacing at which complete shearing was possible between adjacent charges decreased exponentially with a subsequent loss of broken material volume. For charges fired simultaneously, larger burdens and spacings were possible as compared to those necessary for single-crater charges. For each material studied, there was a characteristic optimum charge length and a maximum attainable spacing at any given burden. Proper selection of the spacing distance between charges is fundamental to successful blasting. Its value directly affects the cost of drilling and explosives used per unit of broken material. In addition, the choice of a spacing that is Compatible with a given set of blasting conditions aids in the control of fragmentation sizing, ground vibrations, overbreak, and throw which in turn, influence other production costs. For example, normally loaded blastholes that are spaced too closely invariably promote overbreak and usually give coarse fragmentation. Unless care is taken, airblast and violent flyrock will occur and under certain conditions cutoffs and misfires may result. Too large a spacing, on the other hand, frequently leads to conditions that form bootlegs or toes. The choice of a particular spacicg to use, however, is largely a matter of individual experience and judgment, usually based on trial and error. Very little is known or can be found in the literature with regard to how the spacing between charges is related to field conditions and charge geometry. As a general rule, the firing time sequence of adjacent charges and properties of a material are thought to have the most significant influence on the spacing distance best suited for any given field condition. For example, delayed initiation of adjacent charges usually always requires a closer spacing than when charges are fired at the same time. This should be expected if one considers that the energy normally dissipated and lost in the surrounding ground from charges fired independently would be captured and utilized for breaking material between charges when they are initiated together. Spacing can be extended also when charges are aligned with structural planes of a material, such as jointing, along which shearing is relatively easy. It is customary to relate the spacing (S) between charges to their common burden (B) in the form of a spacing ratio, or SIB. The burden normally is considered as the optimum depth or distance from any single charge perpendicular to the nearest free or open face at which the desired fragmentation and maximum crater yield are obtained. For production blasting, value of the ratio is generally considered to vary from 1 to 2, depending on conditions.1-6 When adjacent charges are fired independent of one another, the value varies from 1 to about 1.4, the closer amount being employed to square corners or produce craters having the ideal 90" apex angle. The larger ratio is the geometric balance value for craters having an apex angle of 135". The basic ideal crater forms in the plane of the charge diameter for charges fired independently are shown in Fig. 1. In the event charges are fired simultaneously, geometric balance in the plane of their charge diameters suggests that a spacing ratio near 2 would be appropriate, as illustrated by Fig. 2. In practice, however, some compromise ratio value must be selected to conform with the specific ground conditions. An example would be where the jointing planes tend to produce 60° or 120° crater angles, the appropriate geometrically balanced charge arrangement being given by Fig. 3. In this condition, the spacing ratio is 1.15, not 1 or 1.4 as suggested for the 90° cratering of independently fired adjacent charges. In view of the foregoing, it would seem logical to assume that whenever charges all having the same burden are fired at the same time, spacing distances always can be greater than those permitted by charges fired independently. In practice this is not the case, however.

Jan 1, 1970

Mansfield MERRIMAN,Lehigh University, South Bethlehem, Pa. (communication to the Secretary*):—The formulas established by Mr. Campbell require the use of tables in order to take into account the influence of manganese on the tensile strength of steel. On examining these tables I find that the quantities given therein may be expressed by simple algebraic forms, so that formulas for tensile strength may be written which can be used without the help of tables. Referring to the case where the carbon is determined by

Jan 1, 1906

By C. R. Whitney, G. N. Maniar, D. R. Muzyka

Previous results have shown that Pyromet 860, an Fe-Ni-base heat-resistant alloy, is stable at temperatures as high as 1500°F for aging times as long as 100 hr. This Paper describes the results of long-time creep-rupture testing at 1050" to 1400°F at various stress levels. Times as long as 37,660 hr were employed. The effects of time, temperature, and stress on the precipitates and their morphologies were studied by optical and electron microscopy, X-ray and electron diffraction, and microprobe techniques. phase, containing cobalt, nickel, and molybdenum, was detected after extended exposures from 1200" to 1400°F and careful study was performed to describe the kinetics of its formation in this alloy. µ phase formation apparently has little effect on the elevated-tem-perature properties of Pyromet 860. For times as long as 500 hr at 1300°F and below, with µ phase present, m significant effects on ambient temperature properties were noted. For longer times at 1300°F and after 1400°F exposure, the effects of u phase on ambient temperature tensile strength properties are not clear due to y&apos; effects and grain boundary reactions. Electron-vacancy, N,, numbers were calculated using different methods described in literature and correlated with the present findings. In the selection of alloys for use in gas turbine applications, structural stability ranks as a primary criterion. High-temperature strength and cost are also of major concern. With these factors in mind, Pyromet 860 alloy, an Fe-Ni-base superalloy was designed. This alloy combines the cost advantages of Fe-Ni-base alloys such as A-286, 901, and V-57 with improved strength and structural stability&apos;1,2 and no tendency to form the embrittling cellular 77 phase. A previous study3 reported on the stability of Pyro-met 860 at temperatures from 1375" to 157 5°F and times up to 100 hr. That study showed that the y&apos; precipitates increased in size and separation and decreased in number with an increase in time or aging temperature. No deleterious phases were found to occur. In the present work, samples from four production heats were subjected to long-time creep-rupture testing at 1050" to 1400°F at various stress levels. Various heat treatments were used on the starting samples and tests were run up to 37,660 hr. The effects of time, temperature, and stress on the precipitates and their morphologies were studied by optical and electron microscopy, X-ray and electron diffrac- tion, and microprobe techniques. Electron vacancy numbers, Nv , calculations were made by TRW.4 Experimental results are correlated with the Nv data used to predict occurrence of intermetallic phases such as a phase. EXPERIMENTAL PROCEDURE Mechanical Tests. Material for the present study came from four production size heats of Pyromet 860 alloy, weighing from about 3000 to about 10,000 lb. All of these heats were made by vacuum induction melting plus consumable electrode vacuum remelting. The nominal analysis for this alloy is compared with the actual analysis of the four heats in Table I. Sections of these heats were forged to 9/16-in. round bar,3/4-in. square bar, 3-in. round bar, 4-in. square bar, and a gas turbine blade forging about 16 in, long, about 6 in. wide, and weighing about 20 lb. In general, all forging of this alloy is done from a 2050°F furnace temperature. Longitudinal test blanks were cut from the centers of the smaller bars, from mid-radius positions for the 3- and 4-in. bars, and from the air foil of the gas turbine blade and heat-treated according to the procedures outlined in Table 11. Heat treatment A is the "standard treatment" recommended for this alloy for best all-around strength and ductility. Heat treatment B is a modification of treatment A for improved tensile strength at moderate temperatures. The treatment coded C was designed for treating large sections according to a procedure previously described.&apos; Heat treatment D was developed to yield optimum stress relaxation characteristics at 1050°F for a steam turbine bolting application. After heat treatment, the test blanks were machined either to plain bar creep specimens with a gage diameter of 0.252 in., to combination smooth-notched stress-rupture bars with a plain bar diameter of 0.178 in. and a concentration factor of Kt 3.8&apos; at the notched section, or to notch-only specimens. All specimens conformed to ASTM requirements. Metallography. Most of the creep-rupture tests were continued to failure. A few bars were fractured as smooth or notch tensiles after creep-rupture exposures. After fracturing, ordinary metallographic sections were made primarily in gage areas adjacent to fractures to represent a "high-stress" region and through specimen threads to represent a "low-stress" region. All metallographic sections were made in a longitudinal direction with respect to the test specimen axes. For optical microscopy, the samples were etched in glyceregia (15 ml HC1, 5 ml HNO,, 10 ml glycerol). For XRD analysis, the phases were extracted electrolytically in two media: 20 pct &Po4 in H20 for selective extraction of y&apos; and 10 pct HC1 in methanol for carbides and other phases.

Jan 1, 1970

By D. J. Wynnemer, G. W. Preckshot

Precise electromotive force measurements have been made on the zinc-cadmium system over the temperature range 700° to 900°C. Activity coefficients, partial free energies, enthalpies, and entropies have been determined .for the entire composition range. The integral heat of mixing is positive and compares favorably with calorimetrically determined values. Vapor-liquid equilibrium compositions were determined .for a total pressure of 1 atm and these agree well with previous values determined in other ways. The use of electromotive force measurements to obtain thermodynamic data for liquid metal systems is a simple and well-known method. Several reviews of the various experimental methods and results have been published.2,3,11 However, most of the past work using this technique was carried out at temperatures slightly above the melting point of the alloy system where alloy composition changes due to vapor transport and increased metal solubility in the electrolyte are not important factors. One advantage of extending the electromotive force measurements up to and including the normal boiling point of the alloy is that it is then possible to evaluate the vapor-liquid equilibrium of the alloy at various pressure levels up to 1 atm. A detailed discussion of the thermodynamics of reversible electromotive force cells can be found in most advanced physical chemistry or chemical thermodynamic textbooks. The expression stating the inter-relation of the electromotive force and the thermodynamic functions is the Gibbs-Helmholtz equation.

Jan 1, 1962

By R. T. DeHoff, L. J. Buteau, J. Kronsbein

Network topology is introduced and used to describe sinter bodies at various stages of the sintering process. The matrices of incidence, loop-branch. tree-branch, and cut-branch are constructed and their relationship to the three-dimensional void space and the common two-dimensional bounding surface is established. The sintering body is assunzed to remain connected but this is not so with the void space. The topological invariants known as Betti numbers are related to this observed fact and provide parameters which measure the progress of the sintering process. They are extracted from the matrices by means of known algebraic operations. Experimental procedures are given which permit actual construction of the various matrices and determination of the Betti numbers by serial sectioning of the sinter bodies. A sinter body is produced by exposing a large number of metallic particles (0.00001 to 0.3 in. diam) to a temperature that is near but below their melting point. When these particles are maintained at such a temperature for a sufficient length of time, it is found that the interparticle contacts become welded. As time increases, these welds, often referred to as necks, grow. All of the space between the particles constitutes a single connected void; an ultimate consequence of sintering is the breaking up of the void into separated parts. A mathematical apparatus for describing the geometric characteristics of a sinter body at each stage of the process was first proposed by F. N. Rhinesl when he introduced the application of topology to this problem. He described the sinter body in terms of one of its topological invariants, the genus. The most important advantage of a topological description is invariance with respect to continuous deformations. This means that particle sizes and shapes need not be considered, resulting in considerable simplification and generalization of the geometric description. In the case of a sinter body, wherein the internal geometry is particularly complex, the simplification provided by topological concepts is absolutely essential. The important parameters in the Rhines model are the number of particles and the interparticle contacts. The invariant considered called genus is given by Euler&apos;s formula for the connectivity of two-dimensional surface of the sinter body. This surface includes the pore-solid interface. The Euler formula is G = C - P + 1 [1] where C = number of interparticle contacts, P = number of particles, and G = genus of the surface bounding the sinter body. In topology the term genus may be used to mean the number of self re-entrant cuts that can be made on a closed surface without dissecting it into more than one connected surface. Its use is restricted to the surface and does not apply to the three-dimensional volume enclosed or excluded by it. In the case of sintering, the volume enclosed by the surface is defined as the sinter body; the volume excluded will be referred to as the void space. There is an intrinsic reason for using genus as a characteristic number associated with a sinter body. The genus is related to the Gaussian curvature by the integral of the product of the principal curvatures taken over the entire surface of the sinter body, as given by

Jan 1, 1965

By John F. Elliott, John P. Hager

The standard free energies of formation of the lowest stable sulfides of chromium, molybdenum, and tungsten in equilibrium with the corresponding metal hazle been determined by reacting the sulfide and metal with H2(g)/H2S(g) mixtures. The reaction is A method for estimating the standard ~nolav entropies and standard entropies of formation at 298°K of the sul-fides of refractory metals is presented. The standard free energies of formation of the lowest sulfides of the metals in group VIa of the periodic table are probably best determined with the reaction* is known with greater accuracy than is that property for any other sulfur-bearing compound or solution which might serve as a reference phase to establish the chemical potential of sulfur for the essential re- However, there still remain significant problems to the use of Reaction [I] in studying these sulfides. First, the equilibrium gas ratios (Ph2S/PH2) are very small, and with the most stable sulfides in the series the ratios tend to be at the limit of the range for precise chemical analysis (10-4); and second, the reaction rate for the formation or reduction of these sulfides appears to be relatively slow. A primary reason for the latter problem is that the gas phase near the equilibrium concentration has very little capacity for transport of sulfur. It is to be noted that the thermo-dynamic properties obtained from the experimental results by Eq. [I] apply for 1 g-atom of sulfur in the metal-saturated compound even though the exact composition of the compound has not been determined. The work reported here is a study of the standard free energies of formation of the lowest sulfides of chromium, molybdenum, and tungsten, and of copper, by Reaction [I]. In planning the experimental program, it was decided that the technique that has been used previously3"&apos; could be used with modification and that an improved analytical method was needed for determining H2S in the gas phase. THE EXPERIMENT The once-through flow of gas was selected in preference to recirculating the gas, a) because of the low sulfur capacity of the gas, b) because of the relatively slow rate of reaction and the danger of the

Jan 1, 1968

By V. O. Struebing, K. A. Johnson, F. H. Ellinger, C. C. Land

The system Pu-Ce-(Pu,Ce)Co2 has been investigated by thermal, micrographic, and X-ray diffraction methods. The principal characteristics of this system were found to be: 1) a "eutectic" valley extending across the phase diagram from the 6 Pu/Pu3 Co eutectic at 408°C to the 7 Ce/Ce24Co11 eutectic at 42Z°C, the maximum temperature in the valley being 443°C; 2) three ternary inter mediate phases, each having an appreciable mutual solid solubility for plutonium and cerium; 3) eleven four-phase equilibria comprising one eutectic, four peritectics, and six Class II reactions; 4) a pseudobinary section between the ternary phase A and the y Ce solid solution, and another such section between the 6 Pu solid solution and the 77 phase (Pu3 CO) containing cerium in solid solution. ALLOYS of plutonium that are completely molten at temperatures in the vicinity of 500°C are of interest for use in the liquid state as fast reactor fuels. Since exploratory work1,2 on Pu-Ce-Co alloys had indicated that a "eutectic" valley extended across the ternary system between the Pu-co[6 Pu/n (Pu3co)] and the Ce-CO[? Ce/? (ce24co11)] binary eutectics, thus allowing alloys of any plutonium concentration to be selected within the temperature limitation, the present investigation was begun for the purpose of accurately defining the "eutectic" valley. However, when the existence of three ternary intermediate phases and the consequent complexity of the liquid-solid equilibria were discovered, the investigation was expanded to cover the complete system, except for the corner between the isomorphous series PuCo2-CeCo2 and pure cobalt. 1) EXPERIMENTAL The purities of the alloy components are given in Table I. Alloy buttons, each weighing about 5 g, were prepared by arc melting the accurately weighed components (±0.1 mg) under a purified He-Ar atmosphere. Weight loss as a result of melting was usually less than 1 part in 1000; therefore, the buttons were not chemically analyzed. One half of each button was re-melted by induction heating in vacuo in a magnesia crucible and furnace-cooled, so as to produce a somewhat coarser microstructure than that of the rapidly cooled arc-melted button. About 20 g of each alloy to be examined by thermal analysis were remelted in vacuo in a tantalum crucible of the inverted thermocouple well type. The thermal, X-ray diffraction, heat treating, and micrographic methods used in this investigation were essentially the same as have been described in earlier reports.3,4 Two etchants for these alloys were found to be satisfactory: A) 8 (parts by volume) orthophosphoric acid, 5 ethanol, and 5 glycol; B) 7 tetraphosphoric acid, 36 water, and 57 2-ethoxyethanol. Etchant A was used at 5 to 6 v for 15 to 20 sec, and etchant B was used at 10 v for 10 sec. 2) THE LIMITING BINARY SYSTEMS 2.1) Plutonium-Cerium. The phase relationships of this system have been investigated by Ellinger, Land, and Cramer,5 and by Selle and Etter.6 The over-all agreement of their phase diagrams is good, but there are some discrepancies in the positions of some phase

Jan 1, 1967

By Gerald Edmunds

The liquidus line on the phase diagram for temperature versus composition of a binary alloy system, representing the boundary between the homogeneous melt and the heterogeneous melt plus solid, besides showing the minimum casting temperature, is useful in determining eutectic compositions and the presence of phase changes such as peritectic transformations and intermetallic compound formation. The liquidus often is determined by the cooling curves of thermal analysis, but supercooling frequently occurs, so that the temperature values are low. An alternative method, the one employed here, consists of determining the composition of samples of the melts from heterogeneous alloys that are at equilibrium. With meticulous attention to fundamentals, this method is capable of yielding values limited in precision only by the temperature control and measurement and analyses. Apparatus By starting, on the one hand, with a supersaturated solution and allowing the excess solute to precipitate, and on the other hand with an undersaturated solution and allowing more of the solute to be dissolved, both processes being carried out at the same temperature, equilibrium may be said to have been approached from both directions; that is, from above and from below. If the analyses show the solutions to contain the same fraction of solute when equilibrium has been approached from above and from below, one is assured that equilibrium has been reached in both determinations. In order to carry out such determinations, it is necessary to have equipment for obtaining and maintaining the proper temperatures; for holding the melt, measuring its temperature, and stirring, sampling and analyzing it. The present work required temperatures from 420° to 900°C. The equipment consisted of: A furnace, which was a vertical alundum tube, 13/4-in. diameter inside and 18 in. long, wound with Nichrome resistance wire, surrounded by a 3-in. i.d. alundum tube wound for 5 in. of length near each end, for compensation of end losses. This muffle was contained in an iron shell with Transite end plates, the intervening space being packed with Sil-O-Cel. The outside dimensions of the furnace were 12 in. in diameter by 181/2 in. in height. Heating current was supplied by three independent variable-voltage transformers (Variac), one connected to each end compensator winding and manually controlled, and one connected to the main winding through a series resistance of 5 ohms. This resistance was short-circuited for

Jan 1, 1944

By Gerald Edmunds

The liquidus line on the phase diagram for temperature versus composition of a binary alloy system, representing the boundary between the homogeneous melt and the heterogeneous melt plus solid, besides showing the minimum casting temperature, is useful in determining eutectic compositions and the presence of phase changes such as peritectic transformations and intermetallic compound formation. The liquidus often is determined by the cooling curves of thermal analysis, but supercooling frequently occurs, so that the temperature values are low. An alternative method, the one employed here, consists of determining the composition of samples of the melts from heterogeneous alloys that are at equilibrium. With meticulous attention to fundamentals, this method is capable of yielding values limited in precision only by the temperature control and measurement and analyses. Apparatus By starting, on the one hand, with a supersaturated solution and allowing the excess solute to precipitate, and on the other hand with an undersaturated solution and allowing more of the solute to be dissolved, both processes being carried out at the same temperature, equilibrium may be said to have been approached from both directions; that is, from above and from below. If the analyses show the solutions to contain the same fraction of solute when equilibrium has been approached from above and from below, one is assured that equilibrium has been reached in both determinations. In order to carry out such determinations, it is necessary to have equipment for obtaining and maintaining the proper temperatures; for holding the melt, measuring its temperature, and stirring, sampling and analyzing it. The present work required temperatures from 420° to 900°C. The equipment consisted of: A furnace, which was a vertical alundum tube, 13/4-in. diameter inside and 18 in. long, wound with Nichrome resistance wire, surrounded by a 3-in. i.d. alundum tube wound for 5 in. of length near each end, for compensation of end losses. This muffle was contained in an iron shell with Transite end plates, the intervening space being packed with Sil-O-Cel. The outside dimensions of the furnace were 12 in. in diameter by 181/2 in. in height. Heating current was supplied by three independent variable-voltage transformers (Variac), one connected to each end compensator winding and manually controlled, and one connected to the main winding through a series resistance of 5 ohms. This resistance was short-circuited for

Jan 1, 1944

By B. H. Bergstrom, D. D. Crabtree, C. L. Sollenberger

Experimental data is given for several natural minerals on the load required for the fracture of single specimens over a very wide size range. The experimental results are compared with published data, such as for coal specimens from 30 to 64 in. in size. Correlations of the specific energy (per unit mass) required for fracture with specimen size are given as functions of specimen shape and the experimentally observed load-size relationships. These correlations are discussed with reference to comminution theory. Comminution, through compression or impact, can result only if sufficient force, or energy, is applied to a specimen of a given size. The relation of specimen size to force requirements has not been adequately considered previously. For single particle fracture, it was previously shown 1 that the specific energy (energy, e, per unit mass, M) at fracture of single glass spheres was inversely proportional to the product size modulus, k, as indicated in the equation: e/M = C/k [1] This was found true not only for numerous glass specimens of the same nominal size but was true for all nominal sizes tested from 1/8 to 1 in. Also, it was observed that the smaller spheres required a greater specific energy at fracture than the larger spheres and consequently had a smaller product size modulus. However, the relationship giving the required fracture energy as a function of specimen size was not further elaborated upon. This paper will extend the development of the feed size effect on specific fracture energy for brittle materials. SPECIFIC ENERGY-FEED SlZE RELATIONSHIPS FROM PREVIOUS DATA For the particular glass spheres tested in the previously described experiments,&apos; it can be shown, as on Fig. 1, that the specific energy varied inversely as the 4/3 power approximately of the feed size, F, in the span of nominal sizes ranging from 1/8 to 1 in. The load at which a 3-in. diam glass sphere (a crystal gazer&apos;s ball) was broken was within the range predicted by an extrapolation of this energy-feed size relationship. The product size distribution from this

Jan 1, 1963