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By Akira Yazawa, Alžbeta Gubcova

RECENT lead-smelting techniques have tended toward use of high-grade concentrates with minimum amounts of flu, accompanied by profitable employment of roast reaction.1-5 In order to better understand these smelting processes, thermodynamical calculations have been carried out on the Pb-S-0 system, and the results obtained have been presented in isothermal reaction diagrams in which log Ps, and logPo, were the axes. The diagram thus constructed seems to be more convenient to grasp the equilibrium aspect than those published hitherto.6-8

Jan 1, 1968

By J. J. Jakosky

The strategic importance of the metallic minerals in our industrial economy, and the declining rates of discovery have focused attention on means of exploration for new mineral deposits. A consideration of exploration techniques leads to an attempt to evaluate the effectiveness of geophysics as a tool for mining exploration. One means of evaluation will be to compare the use of geophysics in petroleum exploration with its possible uses in mining. Geophysics in Petroleum Exploration During the past twenty years, the petroleum industry has established an effective exploration technique. Geology is the basic tool in those areas where reliable predictions can be made from surface conditions. In the other areas, where the geological studies are inadequate, they must be supplemented with geophysics or direct exploration, such as drilling. Since geophysical work is far less costly than any form of direct explbration, it is used almost exclusively as the means for obtaining the desired subsurface information. The geological and geophysical techniques are credited with locating sites which yielded one producer for three dry holes during the year 1947.' For the wells located without geology or geophysics, there is a ratio of one producing well to sixteen dry holes. From these figures it is seen that the geological and geophysical techniques are more than four times as successful as the nontechnical exploration. It will be in order to consider further this ratio of one producer to three dry holes. The geophysical methods in use today† do not pretend to locate oil directly; their function is to locate anomalies or structures favorable for the accumulation of oil. For a producing oil well we must have not only structure, but also other favorable conditions, namely: petroliferous source beds, the required porosity and permeability in the reservoir rocks, an impermeable cap rock over the reser- voir, and the necessary water or gravity drive to force the oil into the bore hole. Since the geophysical work can only detect and sometimes delimit the anomaly, these other necessary conditions can be determined only by direct exploration. The success of modern geophysical work in locating and limiting the structure itself is remarkably high, probably over 95 pct accurate. Geophysical work renders an important service in the delineation of the structurally unfavorable areas and their elimination from the drilling phase of the exploration program. When attempting to locate any material of scarce occurrence in the earth, it is of paramount importance to know where not to dig. This elimination of barren areas is the least appreciated but is of great economic importance. For illustration, the difference between one producer to three dry holes, and one producer to sixteen dry holes, represents a saving of thirteen drilled wells, which would require an expenditure many times the cost of the geophysical work that might have revealed the nonfavorable structural conditions. The percentage of geophysically-located wells necessarily will continue to increase in the statistics of future years, as the search for oil is extended

Jan 1, 1950

By Henry R. Linden

The demand for natural gas continues to increase at higher than anticipated rates, partly because of its widening price advantage over most other fossil fuels when the cost of air-pollution control is included. However, there are clear indications that the natural gas supply from the conliguous 48 states and continental shelves will not keep up with this rapid growth in demand indefinitely. Projections are presented which define the extent of potential deficiencies from the 1970's to the year 2000. Among the sources of supplemental gas - imported pipeline natural gas from Canada and Mexico, tanker import of liquefied natural gas, and synthetic pipeline gas from coal and oil shale -by far the most abundant at potentially competitive costs is pipeline gas from coal. The state of development and relative economics of the various coal gasification processes are reviewed. It is shown that synthetic pipeline gas could become a very substantial market for bituminous coal and lignite at current mine-mouth prices - 60-70 million tons of coal for each trillion cubic feet of synthetic pipeline gas produced. This corresponds to only slightly more than the current annual increase in gas demand. Although annual discoveries (gross additions to proved reserves) of natural gas in the United States are still on a general upward trend from the current level of 22 trillion cu ft annually, most forecasters do not expect this to increase substantially in the foreseeable future. For example, the updated (to include 1966 and 1967 data) mathematical model of natural gas discovery and production in the U.S. developed by the Institute of Gas Technology (IGT)' projects that discoveries will level out at about 25 trillion cu ft annually in the late 1970's and during the 1980's and then decline to about 21 trillion cu ft by the year 2000 (Fig. 1). This adds up to a new supply for the period 1968-2000 of about 790 trillion cu ft. Experts who usually reflect the producers' viewpoint, such as Radford L. Schantz of Foster Associates,* are relatively more pessimistic. In contrast, a forecast just made by the U.S. Dept. of the Interior is much more optimistic.3 It assumes an increase in gas discoveries of 2.2% per year over the period 1965-80, reaching about 30 trillion cu ft in 1980. If this rate of increase were extended to the year 2000, annual discoveries would reach 46 trillion cu ft at that time, for a total over the period 1968-2000 of about 1100 trillion cu ft. To these forecasts of new gas discoveries must be added proved reserves of roughly 290 trillion cu ft,4 bringing total U.S. supplies for the rest of the century to nearly 1100 trillion cu ft (IGT) and possibly as high as 1400 trillion cu ft (U.S. Dept. of the Interior). This is approximately the same range as that of two estimates of total remaining recoverable natural gas supply: Potential Gas Committee, 980 trillion cu ft5 and IGT, 1450 trillion cu ft.6 Only the 1965 estimate by the U.S. Geological Survey7 suggests that economically recoverable natural gas supplies will not be exhausted around the end of the century. These forecasts are, naturally, based on the assumption that changes in technological, economic, and regulatory environment as they affect the gas industry will be of an evolutionary, not revolutionary, nature. The various forecasts of potential natural gas supply must now be compared to forecasts of natural gas demand (Table I). The general consensus is that the recent Future Requirements Committee projection to 1990' (extended to the year 2000 by the most recent U.S. Bureau of Mines (USBM) projection9) represents the minimum gas requirements (Table 11). They add up to a total of 1030 trillion cu ft for the period 1968-2000. Even this minimum anticipated gas demand exceeds the total remaining supply estimate by the Potential Gas Committee and would nearly exhaust the proved reserves plus new discoveries projected by IGT. The supply situation would appear much tighter if the demand projections of the Texas Eastern Transmission Gorp.10 and the American Gas Assn.(A.GA.)'' were used (Table I). Yet, these higher forecasts probably do not include the effects of such new markets as gas fuel cells, use of liquefied natural gas as a transport fuel, etc. They also may not fully reflect the impact of air quality control on the fuel market. Obviously, the probable discrepancy between projected supply and demand can only be accommodated in four ways. 1) Rapid increase in exploration and drilling activity to provide new supplies in the amount projected by the optimistic U.S. Dept. of the Interior forecast, coupled with an increase in net pipeline imports from Canada and Mexico from the present 0.5 trillion cu ft per year

Jan 1, 1970

By Lee Trudick

The secondary dispersion of copper, zinc and fluorine in A horizon soils was examined in Pope and Hardin Counties, IL, by sampling 122 sites along five traverses. Four of the traverses were taken above a deeply buried manto; a fifth intersected a vein complex exposed at the bedrock surface. Plants at each site were examined and analyzed for fluorine and on one traverse for copper and zinc. The A horizon soils were also tested for lead, manganese, barium, nickel and cobalt. The total content of copper, zinc, and other heavy metals in soils was determined by atomic absorption spectrometry (AAS) after acid bomb dissolution. Fluorine in soils was determined by fluoride ion-specific electrode after fusion with NaOH. Several cold- leach methods were also used. The analysis of A horizon soils for copper and zinc by AAS after acid bomb dissolution is a promising geochemical tool in the search for fluorspar. The acid bomb dissolution method is simple and takes little laboratoy time; it Produces a total dissolution of the sample with relatively little loss of the elements, and 20 elements can be analyzed from the same sample. In this study, the highest copper values were 80 times the local background level of 25 ppm and anomalies of this element tended to outline the fluorspar orebody better than either zinc or fluorine. The greatest zinc value was 15 times the local background level of 100 ppm, while the highest fluorine values were approximately four times the local background level of 165ppm.

Jan 1, 1982

By R. M. Genevray, M. B. Bever, E. J. Suoninen

THE martensitic transformation in the ß-phase of the Cu-Zn system has been the subject of several investigations. The transformation is known to be reversible and to be affected by stress. Its temperature range has been determined as a function of composition. In the investigation reported here, the effect of tensile stresses on the transformation was investigated quantitatively. Some information was also obtained on the thermoelastic behavior of the martensite formed in the first stages of the transformation. Most of the experiments were done with alloy E of an earlier investigation;' this alloy analyzed 60.49 pct Cu and 39.51 pet Zn by weight. The methods of shaping and heat treatment were also essentially the same as those previously used. The stress was applied to the specimen immersed in a cooling liquid. The transformation was followed by measuring the electrical resistance with a Kelvin bridge and the elongation with a cathetometer. Fig. 1 shows the M, temperature as a function of stress. Resistance and strain measurements gave essentially identical values. The results suggest a roughly linear relation between M. and in the range investigated, up to 12 kg s mm". At higher stresses, plastic deformation begins to interfere seriously with this relationship. The increase of M, with stress is consistent with published work on the effect of stress on the martensitic transformation. The slope of the curve, 4°C per kg mm ", is of the same order of magnitude as the corresponding value calculated for steel.' Fig. 1 also shows the difference, AM, between the temperature of 50 pct transformation on cooling, as measured by changes in length, and that of 50 pct reverse transformation on heating. This difference, which may be considered a measure of the hysteresis, increases with stress; the decrease at highest stresses is probably associated with plastic deformation. Preliminary work using only resistance measurements was done with an alloy containing 60.15 pct Cu and 39.79 pct Zn by weight. The results indicated higher values o-F M, in agreement with the known variation of M. with composition.' The effect of stress on M, (2°C per kg mm-') was of the same order of magnitude as that shown in Fig. 1 for composition E. An increase in hysteresis with stress was also found. The following experiment was made in order to investigate a partially transformed structure. A specimen of alloy E was cooled to — 85°C under a stress of 4.7 kg mm-'. Under these conditions, the martensitic transformation started but did not go to completion. The stress was then released and the specimen cooled to — 105°C. Fig. 2 shows the measured elongation c. The first change in the slope of the curve indicates the beginning of the transformation under stress. Removing the load at —85°C caused a decrease in length to the value corresponding to the elastic elongation of the parent phase resulting from the applied stress. Hence, the marten-site formed in the first part of the experiment apparently disappears completely and without hysteresis upon the release of the stress. The increase in length on further cooling indicates renewed formation of martensite. These conclusions are consistent with the concept of "thermoelastic" martensite," which has been confirmed by test." Acknowledgments The authors are greatly indebted to Professor M. Cohen for his advice and encouragement. They also thank F. Paxton for assistance. Thanks are due the American Brass Co. which supplied the alloys. References E. Kaminsky and G. V. Kurdjumov: Zhur. Tekhn. Fiziki SSSR (1936) 6, p. 984. A. B. Greninger and V. G. Mooradian: Trans. AIME (1938) 128, p. 337. "J. E. Reynolds, Jr. and M. B. Bever: Trans. AIME (1952) 194, p. 1065; Journal of Metals (October 1952). 'A. L. Titchener and M. B. Bever: Trai~s. AIME (1954) 200, p. 303; Journal of Metals (February 1954). " 3. A. Kulin, M. Cohen, and B. L. Averbach: Trans. AIME (1952) 194. p. 661; Journal of Metals (June 1952). "J. K. Pate1 and M. Cohen: Acta Metallurgica (1953) 1, p. 531. 'C. Crussard: Comptes Rendus (1953) 237, p. 1709. ' G. V. Kurdjumov: Zhur. Tekhn. Fiziki SSSR (1948) 18, p. 999. G. V. Kurdjumov and L. G. Khandros: Dokl Akad. Nouk. SSSR (1949) 66. p. 211.

Jan 1, 1957

By R. W. Fountain, M. Korchynsky

The precipitation phenomena occurring in cobalt-tantalum alloys have been investigated in the temperature range frm 500" to 1050°C by correlating the results of metallographic, X-ray, micro-and macrohardness, and electrical resistivity studies. The property andmacrohardness,changes were found to depend on 1) general precipitation, and 2) lamellar precipitation. Two new intermetallic phases have been identified: 1) a Co3Ta, a metastable ordered face-centered-cubic compound, and 2) a stable ß Co3Ta phase of hexagonal structure. In addition, the previously reported Co2Ta phase was found to exist in two allotropic modifications: the hexagonal MgZn,-type and the cubic MgCu2-type Laves phases. SINCE a large variety of structures can result as a consequence of the decomposition of a solid solution, predictions on the nature of property changes are difficult, if not impossible, to make. For any rational attempt to correlate properties and structures of a precipitation-hardenable alloy, a detailed understanding of the kinetics of decomposition and morphology of phase separation, as well as knowledge of phase relationships, appears to be prerequisite. Information of this type has been accumulated in the past for many alloy systems, both of theoretical and pastforpractical importance.1,2 Although the presence of intermetallic compounds has been reported in cobalt-base alloys,3 the amount of published information on precipitation-hardenable cobalt-base systems is very limited. A survey of the binary phase diagrams of cobalt indicates that cobalt-tantalum alloys might be of interest as typical of other cobalt-base systems in which Laves phases of the A,B type can be precipitated from solid solution. The present work has been undertaken, therefore, to study the kinetics and morphology of the precipitation reaction in this system and to establish a base for a correlation between the structural aspects and properties in this class of alloys. PREVIOUS WORK The only available phase diagram of the cobalt-tantalum system is based on the work of Koster and Mulfinger. According to these authors, the maximum solubility of tantalum in cobalt is about 13 pct (at 1275°C) and. less than 7 pct at room temperature. Tantalum additions lower the temperature of allotropic transformation of cobalt (about 420°C), and at 7 pct Ta, the high-temperature face-centered-cubic modification (ß cobalt) is retained at room temperature. The precipitating phase was originally designated as Co5Ta2 compound (55.2 pct Ta, about 1550°C melting point), but subsequent investigations by wallbaum5" identified this constituent as the A,B-type Laves phase. Wallbaum's data indicate that there are two modifications of this intermetallic compound: one richer in cobalt (Co2.2 Tao.8)of the hexagonal MgNi, type; and another of a higher tantalum content (Co2Ta) of the cubic MgCu, type. On the other hand, Elliott7 found that the cobalt-rich alloy (CO2.10,Tao.~l) was predominantly the cubic MgCu, type at 800°C and a mixture of both the MgCu2 and the hexagonal MgZn,-type Laves phases at 1000°C. At 1200°C, Elliott found only the MgZn, type while at 1400°C, he observed only the MgCu2 type. At the stoichiometric composition, Co2Ta, Elliott reported only the cubic MgCu2-type Laves phase in the temperature range of 600oto 1600°C. The precipitation of the cobalt-tantalum intermetallic compound is accompanied by a marked increase in hardness. According to Koster's4 data, the Brinell hardness of an 8 pct Ta-Co alloy increases from 230 to 340 upon short-time aging at 800°C. EXPERIMENTAL PROCEDURE The binary cobalt-tantalum alloys investigated contained 5, 10, and 15 pct Ta. The range of tantalum additions was thus slightly broader than the reported minimum and maximum solid solubility limits of tantalum in cobalt (7 and 13 pct, respectively)4 The alloys were vacuum-induction melted in a magnesia crucible using cobalt rondelles and technically pure tantalum sheet as raw materials. Deoxidation of the melt was accomplished with carbon, and the chemical analysis of the alloys is given in Table I. The effect of isothermal aging treatments on the progress of precipitation was studied on samples cut from cast ingots. These samples were solution treated for 2 hr at 1250°C and water-quenched. Aging was conducted in the temperature range from 500" to 1050°C for periods between 15 min and 1000 hr and followed by water-quenching. To prevent contamination from the atmosphere, all samples were sealed in evacuated Vycor or quartz tubes for heat-treatments. For solution treatment, argon at 0.2 atmospheric pressure was introduced prior to sealing of the capsule to prevent collapse at high temperature, and titanium sponge was placed at one end of the capsule to act as a getter. MACROHARDNESS The effect of aging on Vickers hardness (Dph) of

Jan 1, 1960

By Albert Sauveur

My first paper dealing with the theories of the hardening of steel by rapid cooling was published in the Transactions of this Institute in 1896— 30 years ago-under the title "The Microstructure of Steel and the Current Theories of Hardening," hence, also, the title of the present paper. It was extensively discussed and was, I believe, one of the starting points of many subsequent papers and discussions of the same subject, dis-cusssions which at times became almost violent and which led to the formation of different schools such as the "Carbonists" and the "Allo-tropists." Some of the older members of the Institute, who took part in the debate or who were interested observers, will, I am sure, have kept a vivid remembrance of it. The controversy gradually quieted down, apparently for lack of ammunition, without any side acknowledging defeat. Recently, however, interest in it ha been revived through the claims of some that these vexed questions had at last been solved. In an effort to ascertain if possible the prevailing view of those best qualified to express an opinion a questionnaire was submitted to the following gentlemen: J. 0. Arnold Sir Robert Hadfield Edgar C. Bain W. H. Hatfield Carl Benedicks Samuel L. Hoyt N. Belaiew Kotaro Honda H. M. Boylston Zay Jeffries Harry Brearley H. Le Chatelier G. K. Burgess H. H. Lester William Campbell Francis F. Lucas H. C. H. Carpenter John A. Mathews Pierre Chevenard A. McCance P. Dejean Albert Portevin C. A. Edwards Walter Rosenhain F. Giolliti Bradley Stoughton G. Grenet F. C. Thompson Leon Guillet

Jan 1, 1926

By J. Wyn Prior

The seismic refraction technique is probably the most popular geophysical method of bedrock profiling in geotechnical site investigations but is somewhat restricted by the inherent assumptions in the method. This paper describes how Hales' method of profile interpretation is modified to overcome the assumptions of increasing velocity and layer thickness with depth when only first arrival data is available. A further expansion of Hales' method enables presentation of refraction data in a form whereby bedrock features, such as changes in velocity, relief and dip in particular, are more readily recognized. Characteristic curves of the more common bedrock features are presented as an aid to bedrock feature recognition.

Jan 1, 1979

By H. J. Engell, W. Frank, A. Seeger

SWISHER and ~urkdogan' have determined the solubility of oxygen in a iron. They found it to lie between 7 and 10.5 at.-ppm at 881°C. Using earlier work on the permeability of oxygen in bcc iron,' they arrived at the following expression for the diffusion coefficient of oxygen in bcc iron (k = Boltzmann's constant, T = absolute temperature): where The present authors3 have estimated the activation energy QD for the diffusion of oxygen in bcc iron in two different ways from various experimental data.2'4"6 In the first method QD + QS (QS = heat of solution for oxygen in bcc iron in thermodynamic equilibrium with solid FeO) was determined either from data on the reduction of FeO with hydrogen4 or from measurements of the internal oxidation of silicon in a iron.5 Using an estimate of QS from investigations of the oxygen solubility in 6 iron2 (in thermodynamic equilibrium with molten FeO) Q = 0.97 ev or Q~ = 1.06 ev were obtained. From the magnitude of these values it was concluded that oxygen migrates interstitially in bcc iron and that consequently the activation energy QD for diffusion of oxygen has to be identified with the migration energy E~ of the oxygen atoms. Therefore, for a second estimate of QD from the diffusion coefficient of oxygen in 6 iron at 1450" ~,~ we used the theoretical expression:3 (a = length of elementary cube edge, m = mass of interstitially diffusing atom, sM = migration entropy), applicable to diffusion via the octahedral interstices in bcc lattices. Taking sM = 3.8 k (migration entropy of carbon in a iron), one gets Q = 0.90 ev. Hence, in Ref. 3 Q = (0.98 *0.1) ev was proposed as a plausible value for the diffusion energy of oxygen in bcc iron. sM + 9 (9 = solution entropy for oxygen in bcc iron) can be determined from permeability measurements.4 Using the above-mentioned estimate for QS , the following expression for the solubility c (atomic concentration) of oxygen (in thermodynamic equilibrium with solid FeO) in bcc iron was derived: From [4] the solubility of oxygen at 881°C in a iron is calculated to lie between 0.6 and 12 at.-ppm. We see that the solubility determined by Swisher and

Jan 1, 1969

By H. Warlimont

Precipitation of cementite plates from carbon-rich austenite gives rise to localized formation of martensite in the matrix next to the precipitate upon quenching. The growth of this martensite is urmsually restricted. A distinct lattice relationship is found between this martensite and the cementite phase. It is concluded that the martensite is nacleated in the region of lowest carbon concentration at the austenite-cementite integace, with low-energy matching to the cementite lattice. The restriction of the growth of the martensite phase to the vicinity of the cementite plates can be explained by misfit in the austenite -martensite glissile interface and the uphill carbon gradient in the austenite. The investigation was carried out by light- and electron-microscopy and by electron-diffraction of thin foils. THE precipitation of cementite from carbon-rich austenite gives rise to a localized formation of martensite in the matrix next to the precipitate upon quenching. This behavior has been described previously by A. B. Greninger and A. R. Troiano1 for a 1.78 pct C steel ("pseudomorphic martensite"), and by A. Hultgren2 for a Fe-0.99 pct C—5.20 pct Mn steel. By measuring the axial ratio of the martensite phase,' it was found that the carbon content of this martensite was lower than that of the martensite which formed without prior partial transformation to cementite. Therefore, it was concluded that lowering of the carbon concentration in the matrix next to the precipitate raised the M, temperature locally and thus led to nucleation of martensite at the ce-mentite-austenite interface. However, the restriction of the growth of the martensite phase to the vicinity of the cementite plates cannot be explained by localized carbon impoverishment alone. Under ordinary conditions a martensite plate which has been nucleated in a favorable site can continue to grow until it encounters a physical barrier, or until it encounters a compositional barrier in the matrix, where the total free-energy change for the reaction is not negative, since it has been shown by numerous experiments that the activation energy for growth of ordinary martensite is virtually zero.' An investigation was conducted by transmission electron microscopy and electron diffraction to study this extraordinary martensite. It was expected that crystallographic in addition to compo- sitional conditions caused this abnormal mode of martensite formation. MATERIAL AND PROCEDURE An Fe-C-Mn alloy containing 1.15 pct C and 5.1 pct Mn was used for most of the experiments. For metallographic work, specimens 15 by 15 by 3 mm were used. For preparation of thin films, the initial specimen size was 15 by 15 by 0.7 mm. The heat treatment of each specimen consisted of austenitizing for 1/2hr at 1100'~ in an argon atmosphere, subsequent isothermal holding in a lead bath at one of a series of different temperatures, and, finally, quenching into brine at room temperature. For metallographic examination, the specimens were mounted in bakelite (slight tempering effects resulted from the heat in the mounting press) ground, polished, and etched in nital. Thin films for transmission electron microscopy and electron diffraction were obtained by grinding the specimens to approximately 0.2 mm thickness and subsequent electrolytical thinning. The orientation relationships were evaluated from sets of electron micrographs and selected-area electron diffraction patterns of single units of the transformation products and the adjacent matrix. RESULTS In the alloy which was used for the experiments, proeutectoid carbide precipitates over a wide tem-

Jan 1, 1962

By K. Unrug, G. Herget, A. Smith

SUMMARY Statistics on roof falls indicate that the cost of just removing the unwanted waste from roof falls in US coal mines amounts to about $20 M per year. Almost 40 percent of fatal accidents occur under permanently supported roofs, indicating that the assessment of roof stability is still a very difficult task. In an effort to obtain a better understanding of roof fall occurrences, rock strength and ground stresses were determined in the roof of one mine each in Western Kentucky, northern West Virginia, and Eastern Kentucky. Triaxial ground stress determinations clearly show that horizontal stresses were higher than vertical stresses, and that maximum stresses in the horizontal plane were concentrated between the NE-SW to E-W direction, with the exception of the Eastern Kentucky site which was above the drainage. Magnitudes of stress components may vary considerably in one drlll hole. Strength tests of roof strata materials were done on core samples. Mapping of roof falls showed that the geometry of an opening or maximum span were not the overruling factor because in the same general area, a roof fall was observed in a room (entry) which connected two stable four-way intersections. It should be noted that, in very wet areas, the roof can break up to the bed where water is carried, and a very low ratio between extent of roof fall to height of roof, fall is observed. Geometry is, however, a contributing factor because nearly 70 percent of roof falls are intersection falls. The frequency of fractures parallel to bedding in failed roof strata is much higher than that observed in the original strata, indicating a significant amount of working in the roof before failure.

Jan 1, 1984

By Cyril Stanley Smith

Somewhat over ten years ago the author described studies1'2 on the constitution of the copper-silicon system. The copper-rich portion of this diagram is shown in Fig. 1. The experimental points freely dotted about the diagram seemed to justify an otherwise unconvincing diagram and for several years the curious reverse bend in the alpha-phase boundary was accepted as substantially correct, even by later investigators3 of the system who introduced changes in the high-silicon phases. The binary diagram has been used as a base for several ternary systems5-9 without any suggested changes. Voce10 suspected the existence of another phase from his study of the cast alloys in the copper-manganese-silicon system, but evidently hesitated to extrapolate this to the binary diagram, particularly in view of the too ingenious explanation that was advanced1' to account for the pools of constituent clearly visible in castings; namely, that they were secondary alpha of twinned orientation deposited from beta. Von Schwarz,12 in 1932, called attention to the fact that this micro-constituent in copper-silicon alloy castings was anisotropic under polarized light and asserted that a new phase, not cubic, should be placed in the diagram .adjacent to alpha. Sautner,l3 on the basis of investigations with the polarizing microscope and with X-rays, introduced this phase into the diagram at about 6 per cent Si. The relevant part of his diagram is shown in Fig. 2. Sautner called the new phase beta, renaming the old beta phase zeta. To avoid confusion, in redrawing Fig. 2 the phases have been renamed in accordance with the terminology adopted in the present paper, in which the new phase is called kappa and the other phases retain the designation given them by Arrhenius and Westgren.4 The thermodynamic impossibility of Sautner's diagram and the paucity of experimental data left the exact location of the new phase field most uncertain, although his work proved beyond doubt that an additional noncubic phase exists. Because of the industrial importance

Jan 1, 1940

By Cyril Stanley Smith

Somewhat over ten years ago the author described studies1'2 on the constitution of the copper-silicon system. The copper-rich portion of this diagram is shown in Fig. 1. The experimental points freely dotted about the diagram seemed to justify an otherwise unconvincing diagram and for several years the curious reverse bend in the alpha-phase boundary was accepted as substantially correct, even by later investigators3 of the system who introduced changes in the high-silicon phases. The binary diagram has been used as a base for several ternary systems5-9 without any suggested changes. Voce10 suspected the existence of another phase from his study of the cast alloys in the copper-manganese-silicon system, but evidently hesitated to extrapolate this to the binary diagram, particularly in view of the too ingenious explanation that was advanced1' to account for the pools of constituent clearly visible in castings; namely, that they were secondary alpha of twinned orientation deposited from beta. Von Schwarz,12 in 1932, called attention to the fact that this micro-constituent in copper-silicon alloy castings was anisotropic under polarized light and asserted that a new phase, not cubic, should be placed in the diagram .adjacent to alpha. Sautner,l3 on the basis of investigations with the polarizing microscope and with X-rays, introduced this phase into the diagram at about 6 per cent Si. The relevant part of his diagram is shown in Fig. 2. Sautner called the new phase beta, renaming the old beta phase zeta. To avoid confusion, in redrawing Fig. 2 the phases have been renamed in accordance with the terminology adopted in the present paper, in which the new phase is called kappa and the other phases retain the designation given them by Arrhenius and Westgren.4 The thermodynamic impossibility of Sautner's diagram and the paucity of experimental data left the exact location of the new phase field most uncertain, although his work proved beyond doubt that an additional noncubic phase exists. Because of the industrial importance

Jan 1, 1940

ARIZONA Established July 10, 1915 ROBERT W. THOMAS. Chairman ROBERT W. HUGHES, Vice-Chairman HUBERT O. WOODS. Secretary-Treasurer American Smelting & Refining CO., Hayden, Ariz. FRANK A. WARDLAW, JR., National Director THEODORE BROOKS I H. C. HENBIE THOMAS C. CHAPMAN P. D. I. HONEYMAN CARL H. COLE JOHN E. LANNING JOHN H. DAVIS ALBERT MENDELSOHN EDWARD G. DENTZER BRENT N. RICKARD MORRIS G. FOWLER F. A. WARDLAW, JR.

Jan 1, 1942

By H. Margolin, E. Ence

A. J. Goldak and J. Gordon Parr University of Alberta) —Margolin and Ence's paper reached us only a few days after we had submitted a paper on the structure of Ti2Cu to the AIME. Here, however, we only wish to point out an error in the paper (page 321): "Karlsson has reported the crystal structure of the first intermediate phase occurring in the Ti-rich portion of the Ti-Cu system to be face-centered tetragonal." Karlsson actually reported the structure of Ti3Cu (i.e., "the first intermediate phase") to be primitive tetragonal with four atoms per lattice point: Cu at 0, 0, 0; and Ti at 1/2, 1/2, 0; 0, 1/2, 1/2; and 1/2, 0, 1/2. Thus, Karlsson suggests a primitive lattice with an ordered arrangement of atoms located at corners and face-centers: Ence and Margolin suggest a random body-centered tetragonal structure—-with which our results agree. E. Ence and H. Margolin (azlt1zo.l-s' reply)— We do not agree that Karlsson has not reported the structure of Ti3Cu as face-centered tetragonal. The fact that Cu atoms are located at the corners and titanium at the face-centers does not indicate that the lattice is not face-centered. We are pleased that the discussers' results agree with our own.

Jan 1, 1962

By George M. Fowler, R. E. Illidge

Part I. Developing BY GEORGE M. FOWL INTRODUCTION The Tri-State district comprises an area of about 2000 square miles in southwestern Missouri, southeastern Kansas, and north [ ] eastern Oklahoma. The part that is in and contiguous to Missouri is still sometimes designated as the Joplin district (Fig. I). EARLY OPERATIONS Mining operations in what is now the Tri-State district date from about 1848 and have been continuous to the present. Apparently the first discoveries of ore were made about the same time near the present sites of Joplin, Oronogo, and Granby. Lead minerals were found at grass roots, probably in shattered rock in shallow excavations, then these minerals were followed in shear zones to deeper horizons. The mining of zinc followed. Before 1874, zinc ore was worthless and discarded as waste. According to published records, the total production of lead to that date was 49,000 tons of metal from 70,000 tons of concentrates. PRODUCTION The aggregate ore production from the Tri-State district was recorded at interval

Jan 1, 1943

By Owen S. Roberts

During the design phases of a conveyor system, the question arises regarding the type of drive required for each application. The paper shows that the correct drive for any particular application is the one that satisfies the criteria established for that application in the most economical manner consistent with such considerations as site location, availability of spare parts, area environmental conditions, power supplies available, etc. Following discussions of various mechanical arrangements for the drives, motor types and their characteristics are considered along with the control means of modifying these characteristics to satisfy individual requirements. These characteristics are all illustrated graphically. After selecting the motor and its starter, control accessories and interlocking arrangements as applied to material handling systems are discussed.

Jan 1, 1973

By J. S. Aronofsky, A. S. Lee

Results and experimental procedures are presented covering a preliminary laboratory investigation of the compaction of reservoir rocks and its effect on porosity and permeability. "Egective" compressibility was measured by subjecting core material to an overburden load and reducing pore pressure. Preliminary results showed relatively high effective compressibilities which varied from 1.8 X 10-' pore volume/pore volume /lb / in.~ for limestones to 7.7 X 10-6 pore volume/pore volume/lb/in.' and even higher for sandstone reservoirs conmining large amounts of fine clay material. It appeared from the initiol results that the effective compressibility of the material could not be correlated directly with porosity and that other factors, such as the amount of clay material present might have to be taken into account. The work to date has indicated that effective compressibility factors will have to be measured for the particular reservoirs heing studied. Oil permeability of core materid was measured under various effective overburden loads from 0 to 8,000 psi. It has been found than reduction of permeability in clean sands was relatively small and the results agreed with published data. For sandstones containing large amounts of clay, preliminary tests indicated very large reductions in permeability with increasing effective overburden pressures. It is planned to continue laboratory work on this phase because of its importance in low-permeability reservoirs. INTRODUCTION During the past few years increasing interest has been shown in the differences obtained between conventional laboratory measurements on cores at atmospheric pressure and those when reservoir conditions are simulated. Since these data are used as the basis for calculations and the prediction of reservoir behavior, their evaluation under reservoir conditions is most important. The effect of the compressibility of the rock upon the reservoir behavior, as fluid pressure declines, is an important subject which has been insufficiently studied. The total pressure on any plane through a reservoir is the result of the grain-to-grain rock pressure due to the overburden and the pressure of the interstitial fluid on the plane. As reservoir fluid pressure declines, the net load on the rock phase must increase, and the result is the compaction of the rock structure which produces a decrease in pore volume. Simultaneously, the rock grains expand into the pore space as the fluid pressure declines. The result of these two effects is defined as the effective compressibility of the rock and is expressed in units of pore volume/original pore volume/psi. Work was started by Imperial in 1954 on the effects of pressure on the porosity of reservoir rock. These studies established effective compressibility factors for some limestones and dolomites. Since that time effective compressibilities have been obtained for other Canadian and some U. S. reservoir rocks. In conjunction with the study of porosity, an investigation has also been initiated to determine the effects of pressure on permeability. One outcrop and several reservoir sandstone cores have been tested to date. ROCK COMPRESSIBILITY Apparatus anD Procedure A diagram of the apparatus used in these studies is shown in Fig. 1. The equipment was constructed so that a uniform pressure, equivalent to the reservoir overburden, could be applied by the oil pump and transmitted on all sides of the core through the Lucite sheath. The sample was completely saturated by circulating brine through the mounted core. Pressure in

By Jei Y. Choi, P. G. Shewmon

Using a scratch smoothing technique, the magnitude and the ratio of the surface diffusion coefficients (D,) in two orthogonal directions have been measured on copper for over 100 different surface orientations. Anisotropy was found for all surface orientations except those lying near the (100) and (111); however, these anisotropies were rarely greater than 2.0. The direction of maximum D, appears to coincide with the direction of step edges on any given surface, and if no such steps exist, no anisotropy is found. Thus the jump frequency along a step edge is shown to be faster than the frequency of a jump over the step. The values of Ds and AH for the (100) and the (111) orientations agree quite well with those obtained earlier by the grain boundary grooving technique. It is proven that the directions of maximum and minimum D, (the principal axes) for any surface orientation are known if the perfectly ordered plane corresponding to the given surface orientation possesses a plane of mirror symmetry. Thus the principal axes of D, for orientations lying along the sides of the unit stereo-graphic triangle are always known independent of the extent of thermal disorder or impurity adsorption. The merits and shortcomings of King and Mullins' recently published equations relating Ds to the rate of scratch smoothing are discussed. 1N an earlier paper the authors have reported the variation of the surface diffusion coefficient (Ds) with surface orientation on copper.' In that study Ds was determined from the rate of growth of grain boundary grooves on symmetric bicrystals. This gave values of Ds from 850° to 1070°C in a given direction on each of the six surfaces. It was found that the activation energy for surface diffusion was essentially the same for all six surfaces. The theory developed to explain these data assumed that the free energy of any given type of surface site depends only on the number of nearest neighbors the atom has. This same theory predicted that on any given surface Ds should be independent of direction. The primary aim of this study was to check the validity of this prediction for a wide range of surface orientations on copper. The growth of grain boundary grooves is ideal for studying Ds in a given direction on a given surface over a range of temperatures, because the same specimen can be repolished and used again. However, there is considerable work involved in growing a symmetric bicrystal, and for a survey of Ds in two or more directions on many surface orientations, the technique would be arduous. A better technique appeared to be the scratch method used primarily by Mykura. 2 If a scratch is placed in a surface whose surface tension is independent of orientation, the surface will smooth out in time under the influence of surface tension. To determine D, from this flattening, Blakely and Mykura2 used an approximate solution which was assumed to describe the rate of flattening. Recently King and Mullins3 (hereinafter K and M) have given a more exact analysis of the flattening of an isolated scratch. A second aim of this paper was to check the validity of this newer analysis and compare the values of Ds determined thereby with the values obtained from grain boundary grooving techniques. EXPERIMENTAL PROCEDURE In an effort to work with a particular predetermined surface orientation, light orthogonal scratches

Jan 1, 1963

By D. J. DeLazaro, W. Rostoker, R. E. Riley, M. Hansen

KNOWLEDGE of the isothermal transformation behavior and the TTT chart method of graphically summarizing such information has been of invaluable aid to the ferrous metallurgist in understanding and developing heat treatments intended to provide specific mechanical properties. It is to be expected that similar lines of study directed to titanium-base alloys will be as profitable. This paper summarizes, on conventional TTT charts, the isothermal transformation products and pertinent reaction rate data for binary alloys of titanium containing 1, 3, 5, 7, 9, and 11 pct Mo, respectively. The results so presented were derived from metal-lographic examination. Some X-ray diffraction work was done to clarify certain points of question. Ti-Mo System To the authors' k.nowledge, TTT charts have only been used to describe the reaction rates of eutectoidal decompositions. It would seem that the kinetics of decomposition of any unstable solid solution might be conveniently described in this manner. The equilibrium diagram of the Ti-Mo system' is shown in Fig. 1. The similarity with the Fe-Ni system will be recognized. Additions of molybdenum serve to stabilize the /3 phase to increasingly lower temperatures. The solubility of molybdenum in the a phase is restricted to less than 1 pct at 600°C. Under normal conditions. a homogeneous ,8 structure quenched to a, temperature in the a f & field will reject a of invariant composition. The rate at which this occurs depends on the degree of undercooling and the degree of supersaturation of /3. The structural character of the rejected phase may also be expected to be related to the undercooling. Materials and Experimental Methods A sponge titanium was used which has a nominal impurity content as reported in Table I. The nominal composition of the molybdenum used is also included. The alloys were prepared in 150 g melts by arc melting in an evacuated water-cooled copper crucible of the type reported in an earlier paper.' The pancake-type ingots were forged to 1/4x1/4 in. bars and homogenized for 24 hr at 1000°C in evacuated Vycor bulbs. Specimens Vi in. thick were cut from these bars for heat treatment. The heat treatment cycles followed an invariant procedure. The specimens were soaked at 1000°C for 20 min under a helium protective atmosphere prior to quenching into a lead bath held at a temperature corresponding to a chosen degree of undercooling. After a prescribed period of time at this temperature, the specimen was removed and water quenched. A series of specimens so treated for progressively longer periods served to establish the times for initiation and completion of the decomposition of the /3 phase at a particular temperature. Although heat treatment of unprotected specimens in a lead bath does permit surface contamination by lead diffusion, this method is necessary to insure sufficiently rapid quenching rates. As long as the bath treatments were of less than 1 hr duration. the contaminated surface was not unduly deep and could be removed without excessive grinding. Metal-lographically, the contaminated zone could be readily distinguished from the pure binary alloy. Transformation Characteristics of Ti-Mo Alloys Metallographic examination showed that a supersaturated p phase may decompose by one of two processes. Alloys containing 1 to 9 pct Mo, when quenched in water from the homogeneous /3 field,

Jan 1, 1953