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By R. G. Vardiman, M. R. Achter

THERE has been interest recently in the conditions under which dislocation pipe diffusion may be observed. In order to extend the measurements to temperatures below Tm/2, where pipe diffusion becomes more important, a chemical sectioning technique was developed for silver single crystals which makes possible the removal of layers of 100A or less. The procedure is briefly as follows. Silver single crystals of 99.995 pct purity were cut in the form of discs t by 4 in., electropolished, and electropolated with Ag110 to about 1000A thickness. The thickness was determined by calibrating the activity with the weight of heavier platings, up to 10,000A. Both diffused and undiffused samples were sectioned in a two-step process. Reaction with a solution of iodine in alcohol formed a thin, even layer of AgI, which was then dissolved in a KCN solution. The reaction rate of the iodine solution varied slightly over a period of time, so that the thickness of the stripped layers, while quite even and regular for a given specimen, ranged from 65 to l00W for different specimens. This variation was checked by using a thickly plated standard with each run. Layer thickness was determined from undiffused samples by the point where the layer activity drops to half the maximum. This maximum intensity also provides, with appropriate corrections, the initial concentration per layer co. Because of the small penetration distances, it is necessary to use the exact solution of Fick's law for a source of finite thickness.' For a plating of thick- where c is the concentration at depth x. flj the error function, D the apparent diffusion coefficient, and t the time. The diffusion coefficient was obtained from the concentration-penetration data by extrapolating to x = 0 where c/co = erf h/2(Dt)1/2 Enough points were taken to impart confidence in the accuracy of the intersection, generally about ten layers. Four temperatures were used as in Table I. For best accuracy, t and h were chosen to give values of the parameter (Dt)1/2/h between 1.0 and 1.7. A typical concentration-penetration curve is shown in Fig. 1. The diffusion coefficients calculated from Eq. [I] are plotted in Fig. 2. For comparison, the high-temperature data of Tomizuka and sonder 2 which go down to 630°C are plotted as the solid line 2(a) from their expression D = 0.40 exp (-44,090/RT). Also for comparison, the lowest temperature point of Hoffman and Tumbull3 is plotted. It is apparent that our data diverge appreciably from the high-temperature extrapolation by 373°C. A better straight line fit for the low-temperature portion is obtained by subtracting the extrapolated volume diffusion coefficient from the apparent. or measured coefficient, and plotting the difference, curve (h) of

Jan 1, 1970

By W. N. Poundstone, P. C. Thakur

Introduction Horizontal drilling in coal mines is a relatively new technology. The earliest recorded drilling in the United States was done in 1958 at the Humphrey mine of Consolidation Coal Co. for degasification of coal seams. Spindler and Poundstone experimented with vertical and horizontal holes for several years. They concluded in 1960 that horizontal drilling in advance of underground mining appeared to offer the most promising prospect (for degasification) but effective and extensive application would be dependent upon the ability to drill long holes, possibly 300 to 600 m, with reasonably precise directional control and within practical cost limits (Spindler and Poundstone, 1960). Mining Research Division of Conoco Inc., the parent company of Consolidation Coal Co., began a research program in the early 1970s to achieve the above objective. The technology needed to drill nearly 300 m in advance of working faces was developed by 1975 and experiments on advance degasification with such deep holes began in 1976. Preliminary results of this research have already been published (Thakur and Davis, 1977). To date nearly 4.5 km of horizontal holes have been drilled for advance degasification and earlier results were reconfirmed. In summary, these are: • The greatest impact of these boreholes was felt in the face area where methane concentrations were reduced to nearly 0.3% in course of two to three months from original values of nearly 0.95%. • The methane concentration in the section return reduced to 50% of its original value immediately after the boreholes were completed, indicating a capture ratio of 50%. • The total methane emission in the section (rib and face emission plus the borehole production) did not increase but rather gradually declined with time. • Initial production from 300 m deep boreholes in the Pittsburgh seam varied from 3 m3/min to 6 m3/min but then slowly declined as workings advanced inby of the drill site (well head) exposing a larger surface area parallel to the borehole. Encouraged by these results, it was decided to design a horizontal drilling system that would be mobile and compatible with other face equipment. A mobile horizontal drill can be divided into three subsystems: the drill rig, the drill bit guidance system, and borehole surveying instruments. The drill rig provides the thrust and torque necessary to drill 75- to 100-mm diam holes up to 600 m deep and contains the mud circulation and gas cuttings separation systems. The drill bit guidance system guides the bit up, down, left, or right as desired. Borehole surveying instruments measure the pitch, roll, and azimuth of the borehole assembly. Additionally, it also indicates the thickness of coal between the borehole and the roof or floor of the coal seam. Thus, it becomes a powerful tool for locating the presence of faults, clay veins, sand channels, and the thickness of coal seam in advance of mining. In recent years, many other potential uses of horizontal boreholes have come to light, such as in situ gasification, longwall blasting, improved auger mining, and oil and gas production from shallow deposits. The purpose of this paper is to describe the hardware and procedure for drilling deep horizontal holes. The Drilling Rig [Figures 1 and 2] show the two components of the mobile drilling rig: the drill unit and the auxiliary unit. The equipment (except for the chassis) was designed by Conoco Inc. and fabricated by J. H. Fletcher and Co. of Huntington, WV. The drill unit. It is mounted on a four-wheel drive chassis driven by two Staffa hydraulic motors with chains. The tires are 369 X 457 mm in size and provide a ground clearance of 305 mm. The prime mover is a 30-kw explosion-proof electric motor which is used only for tramming. Once the unit is Crammed to the drill site, electric power is disconnected and hydraulic power from the auxiliary unit is turned on. Four floor jacks are used to level the machine and raise the drill head to the desired level. Two 5-t telescopic hydraulic props, one on each side, anchor the drill unit to the roof. The drill unit houses the feed carriage, the drilling console, 300 m of 3-m-long NQ, drill rods, and the electric cable reel for instruments. The feed carriage is mounted more or less centrally, has a feed of 3.3 m, and can swing laterally by ± 17°. It can also sump forward by 1.2 m. The drill head has a "through" chuck such that drill pipes can be fed from the side or back end. General specifications of the feed carriage are: [ ] The auxiliary unit. The chassis for the auxiliary unit is identical to the drill unit but the prime movers are two 30-kW explosion proof electric motors. It is equipped with a methane detector- activated switch so that power will be cut off at a preset methane concentration in the air. No anchoring props are needed for this unit. The auxiliary unit houses the hydraulic power pack, the water (mud) circulating pump, control boxes for electric motors, a trailing cable spool, and a steel tank which serves for water storage and closed-loop separation of drill cuttings and gas.

Jan 1, 1981

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

New York Meets first Wednesday after first Tuesday of each month. DAVID H.-BROWNE, Chairman, JOHN H. JANEWAY, Vice-Chairman. F. E. PIERCE, Secretary, 35 Nassau St., New York, N. Y. P. A. MOSMAN, Treasurer. LEWIS W. FRANCIS. Boston Meets first Monday of each winter month. HENRY L. SMYTH, Chairman. . ALFRED C. LANE, Vice-Chairman. HENRY A. WENTWORTH, Secretary-Treasurer, 60 India St., Boston, Mass. ROBERT H. RICHARDS, ALBERT SAUVEUR. Columbia Holds four sessions during year. Annual meeting in September or October. FRANK A. ROSS, Chairman. RUSH J. WHITE, Vice-Chairman. LYNDON K. ARMSTRONG, Secretary-Treasurer, P O. Drawer 2154, Spokane, Wash. FREDERIC KEFFER, FRANCIS A. THOMSON.

Jan 11, 1915

By Ernest G. Enck

"The Rockets' Red Glare" of the Fourth of July is produced by strontium compounds. However, strontium has a number of less spectacular uses; i.e. in, or in connection with, the manufacture of ceramics, caustic soda, glass, railway and truck signal flares, beet sugar and steel. The principal ore of strontium for use both as the mineral and for production of compounds is celestite (SrSO4). This mineral varies in color from white to pink or blue depending on presence of impurities. It has a hardness of about 3.5 and specific gravity of 3.9. It is brittle and has perfect basal and prismatic cleavages. The high grade ore is obtained from England, hence it has become the standard for all other producing areas. (See analyses, Table 1.) The most objectionable impurity in English celestite is iron, coming mostly from adhering clay. On the other hand, Mexican celestite, while no higher in strontium sulfate content, is extremely low in iron (less than 0.2 pct), hence it is more desirable for certain uses. Most of the celestite in Spain and in the United States is high in calcium and barium, and commonly high in iron, and requires some form of beneficiation in order to be equal to English ore. The natural carbonate (SrCO3), or strontianite, is less important than celestite as a source of strontium, because it is less abundant and is not so widespread in its occurrence. Furthermore, it generally occurs with calcite (CaCO3) and lead sulfide (PbS), and for most uses these impurities are detrimental. This mineral is generally white or yellowish, forming needle-like crystals. It has a hardness of about 3.7 and a specific gravity of 3.68-3.8. The mineral is brittle and has an imperfect cleavage. A typical analysis of German strontianite is shown in Table 1. [ ] Distribution of Deposits UNITED STATES Occurrences of strontium minerals are known in Arkansas, Arizona, California, Illinois, Ohio, Pennsylvania, Tennessee, Texas, and Washington. Celestite occurs in the Vulture Mountains, Maricopa County, Arizona in beds three to ten feet thick associated with sandstone, gypsum, and barite. Because of the low strontium content, approximately 86 pct SrSO4, it has no commercial value. A large deposit of celestite occurs in San Bernardino County, California, in the Cady Mountains near Argus Station, about eight miles west of Ludlow. The celestite here is interbedded with shaly and clayey tuff in a zone about 300 ft thick. Massive, finely crystalline ore has been recovered with an analysis

Jan 1, 1960

By William R. Webster

At the Florida meeting of the Institute, in March, 1895, I presented a Note on a Proposed Scheme for the Study of the Physics of Cast-Iron,1 giving an outline which, for convenience of reference, I here repeat. Suggested Lines for DiScuSsion and IvestiGation. I.—Correspondence between chemical composition and melting-point, fluidity, shrinkage, fracture, chill, micro-structure, and other physical properties. II.—Influence of: 1. Cupola-mixture, use of steel and other scrap, oxidized or clean material, 2. Manner of melting, flux, etc., 3. Casting-temperature, A. Fracture. 4. Manner of handling melted metal and B. Micro-structure. method of casting, C. Physical properties. 5. Size and form of casting, D. Shrinkage. 6 Kind of mold, green sand (under dif- on E. Chill. ferent conditions of ramming, amount F. Residual strew of moisture, and skin-dried), dry sand, G. Condition and quan- loam, and chills, tity of carbon and 7. Rate and mode of cooling castings, other elements. 8. Manner and temperature of heating for annealing, 9. Additions of nickel or aluminum, III. —-Segregation as affected by : 1. Composition ; 2. Casting-temperature; 3. Rate of cooling ; 4. Size and shape of casting. IV. —Blow-holes, their volume and position as affected by: 1. Composition; 2. Casting-temperature; 3. Casting-pressure ; 4. Rate of cooling; 5. Size and ehape of casting ; 6. Special additions. It was hoped that a discussion might thus be elicited, similar in interest and value to the discussion of the physics of steel, which had been so widely and gratefully welcomed by students and practitioners in that department. That this hope was not

Jan 1, 1905

New York Meets first Wednesday after first Tuesday of each month. DAVID H. BROWNE, Chairman, JOHN H. JANEWAY, Vice-Chairman. F. E. PIERCE. Secretary, 35 Nassau St., New York, N. Y. P. A. MOSMAN, Treasurer. LEWIS W. FRANCIS. Boston Meets first Monday of each winter month. HENRY L. SMYTH, Chairman. ALFRED C. LANE, Vice-Chairman. HENRY A. WENTWORTH, Secretary-Treasurer, 60 India St., Boston, Mass. ROBERT H. RICHARDS, ALBERT SAUVEUR. Columbia Holds four sessions during year. Annual meeting in September or October. FRANK A. ROSS, Chairman. RUSH J. WHITE, Vice-Chairman. LYNDON K. ARMSTRONG, Secretary-Treasurer, P. O. Drawer 2154, Spokane, Wash. FREDERIC KEFFER, FRANCIS A. THOMSON.

Jan 8, 1915

By E. C. W. Perryman

IN spite of the large amount of work which has been carried out on the recrystallization of aluminum and its alloys, there has been no complete investigation of the recrystallization characteristics of A1-Mg alloys. The most complete investigation is that reported by Bungardt and Osswald' who, working with commercial-purity materials, found that the temperature both of beginning and of complete recrystallization increased with magnesium content up to about 2 pct Mg, then decreased with a further increase in magnesium up to 5.0 pct, and thereafter increased again. Michaud and Segolz working with 99.93 pct A1 also found the temperature of beginning of recrystallization to decrease as the magnesium content increased from 2.13 pct to about 4.5 pct. Chossat3 using aluminum of 99.99 pct purity found that 0.12 pct Mg had no effect but that 0.4 pct Mg increased the recrystallization temperature by about 30°C. That no effect was found for 0.12 pct Mg does not agree with the later results reported by Demer and Beck4 who found that 0.025 pct Mg in 99.99 pct A1 increased the time for complete recrystallization and furthermore increased the activation energy for the recrystallization process. Kratz" using 99.997 pct A1 found that 0.5 pct Mg increased both the temperature of beginning and of complete recrystallization by 100°C. Chadwick and Hooper" working with commercial-purity material found that 1 pct Mg increased the temperature of complete recrystallization by about 40 °C for cold reductions in the range 17 to 72 pct. With smaller amounts of cold work produced by stretching (10 pct strain), they found no significant effect of magnesium. The latter result agrees with that obtained by Williams and Eborall' who found no effect of 2 pct Mg on the recrystallization temperature of commercial-purity aluminum strained 10 pct or less by stretching. Experimental Procedure Material Used: The chemical analyses of the materials used throughout this investigation are given in Table I. Fabrication: The alloys were cast in iron molds which had been washed thoroughly with alumina. After scalping, the ingots were annealed for 16 hr at 450°C, pressed, annealed at 450°C for 16 hr and hot rolled to 0.25 in. After hot rolling, the slabs were alternately annealed and cold rolled to 0.036 in. Cold-rolling reductions between intermediate anneals were kept at about 30 pct and a high intermediate annealing temperature of 450°C was used so as to obtain, as nearly as possible, similar starting grain sizes for the different materials. All intermediate anneals were done in a salt bath and were followed by cold-water quenching so as to retain all the magnesium in solid solution. The final cold reductions investigated were 20, 30, 40, 50, 60, and 80 pct. The initial grain sizes, that is, the grain size before the final cold reduction, were all very similar. Annealing Procedure: Specimens, 1 in. sq, were cut from the 0.036 in. sheet and annealed in a salt bath, the temperature of which was controlled to k2"C. Separate specimens were annealed for different times at 350°, 375", 400°, and in one or two cases at 415°C and after annealing were quenched in cold water. The time taken for a specimen to reach temperature was approximately 5 sec. Metal-lographic examination after annealing showed that no precipitation of Mg+413 occurred during cooling. Procedures Used for Determining Recrystallization Characteristics: All specimens were electrolyti-cally polished and etched by the method described previously1° and polishing was continued until about 0.002 in. had been removed from each side of the specimen. Using this technique, the smallest recrys-tallized grain which could be observed with cer-

Jan 1, 1956

The manpower and time involved in primary blasthole stemming at Kennecott Copper Corp.'s Bingham Canyon mine have been reduced considerable through the use of a mobile stemming machine invented y three mine employees. The patented machine, developed 2% years ago at an estimated cost of $5000 for two units, is the brainchild of Thomas R. Carlson, mine plant superintendent; Alvin J. McIntosh, drilling and blasting engineer; and Jay K. Buehler, field repair general foreman. According to McIntosh, the machine has been well received by the mine employees, who have been relieved of the tedious task of hand shoveling drill cuttings into the blastholes. It is estimated that the stemming machine has saved the mine approximately $25,000 per year in overtime and regular labor costs.

Jan 12, 1976

By AIME AIME

BECAUSE of its unequalled skill, your country in- creased its production until, in 1913, it produced 40 per cent. of the world's consumption of coal, iron ore, and cast iron; 45 per cent. of the steel; and 60 per cent. of the copper. Your industrial effort, in a general manner and your mining effort in particular, has been tremendous. In the general economy of the world, you occupy an incomparable position of power and action. All your curves of production, mineralogical, metallurgical, financial, commercial, have taken terrific trigonometrical tangents and you will easily under- stand the sorry position of your competitors. I must, therefore, pay a tribute of homage arid admiration to you all who, each in his sphere, have been the artisans of such prosperity and my earnest wish is that you continue in this way.

Jan 1, 1920

Executive FREDERICK M. BECKET, Chairman HOWARD N. EAVENSON J. V. W. REYNDERS H. A. GUESS WILLIAM WRAITH Finance HENRY KRUMB, Chairman PAUL H. MERCER H. G. MOULTON Admissions JOHN M. LOVEJOY, Chairman GEORGE D. BARRON DONALD M. LIDDELI. E. V. DAVELER W. D. B. MOTTER, JR. Alternates AMOR F. KEENE L. F. STROBEL SAM TOUR Membership LEWIS B. LINDEMUTH, Chairman EDWARD H. ROBIE, Secretary Executive Committee NELSON DICKERMAN FREDERICK LAIST FRED H. KAY THOMAS T. READ H. A. KURSELL A. T. SHURICK SAM TOUR

Jan 1, 1932

By J. A. Jaekel, W. C. Aitkenhead

Uranium deposits in the Spokane Indian Reservation, as well as those around Mt. Spokane, are essentially low grade, much of the ore containing less than 0.2 pct U3O8. The Mining Experiment Station of the Division of Industrial Research, State College of Washington, has been engaged in intensive research on the amenability of these low grade ores to froth flotation. The results: successful flotation of autinite, chief mineral constituent. At the outset of this work the goal was a concentrate of 1 pct U3O8 with a 90 pct recovery from ores containing less than 0.2 pct U3O8. Most of the work has been done on argillite ore from the Midnight mine on the Spokane Indian Reservation. The goal has not been attained using this ore, but samples of the granite ore from Mt. Spokane yielded successful results. For example, a concentrate containing 11.2 pcl U3O8 was produced from a Mt. Spokane high grade ore containing 1.27 pct U3O8 with a recovery of 97.8 pct. Another Mt. Spokane ore yielded a concentrate of 5.0 pct U3O8 from an ore containing 0.13 pct U3O8. with a recovery of 85 pct. This same ore gave a recovery of 93.5 pct when the grade of concentrate was reduced to 2.0 pct. It has been concluded that a successful method for floating autunite has been developed and that the mediocre results from the Midnight argillite ore are probably caused by the presence of some other uranium mineral or minerals less amenable to these reagents. The experimenters tested a third type of Washington ore, found on the Northwest Uranium Mines Inc. property on the Spokane Indian Reservation. This is a conglomerate of pebbles and small boulders of partially decomposed granite and is shot through with autunite. Its characteristics lie between those of the Midnight ore and the granite ore from the Spokane district. It responds better than the ore from Midnight but not as well as that from Mt. Spokane. As the fatty acids are the only type of collectors showing promise, investigation has been concerned with these acids and the optimum conditions for their use. The first method for treating the argillite ore from the Spokane Indian Reservation made use of Cyanamid's R-708 as a collector, a tall oil product described as a substitute for oleic acid. Although the investigators proved that R-708 is a collector for autunite when mixtures of autunite and silica sand are used, results on the ore were mediocre. Tests of other fatty acids revealed that the solid fatty acids of the saturated series are collectors for autunite and that their collecting power increases with the length of the carbon chain. The even carbon members of the whole series were tested from the 10 carbon acid (capric) to the 22 carbon acid (be-henic). The least expensive collector, stearic acid (18 carbon), proved to be a good one, so this was used in most of the tests. In first attempts with stearic acid, the collector was dissolved in various hydrocarbons and the solutions were added to the flotation cell. Cyclohexane, gasoline, fuel oil, kerosene, and other solvents were tried. Small amounts of high grade concentrates could be brought up, but recoveries were low. Finally emulsions of stearic acid were tried. It was discovered that stearic acid alone has little collecting power except when conditioning is carried out at high temperature. When hydrocarbon solvents were also present, it proved to be an excellent collector. An example of one emulsion that proved satisfactory for some ores is given as follows: 1 part stearic acid by weight, 1 part sodium oleate by weight, 1.2 parts kerosene by weight, 100 parts water. In some successful tests part of the stearic acid was replaced by oleic acid. The emulsions were made by agitating the stearic acid and sodium oleate together with hot water, then adding the kerosene and agitating while cooling. In the five tests reported in Table 1, 650 g of ore were ground with 650 cc water in a laboratory rod mill. The pulp was filtered to eliminate excess water and the ground ore transferred to a stainless steel beaker for conditioning at high pulp density. In most of the tests sodium hydroxide was added to the conditioner during agitation, then the collector emulsion, and finally the sodium silicate. The amount of alkali was adjusted to give a pH of 8.5 to 9.0 in the flotation cell. After conditioning the pulp was transferred to a laboratory flotation cell and the test completed in a normal manner. It is interesting to note that a deposit of high grade concentrate forms on the conditioning agitator and in the conditioning vessel, and at times on the agitator of the flotation cell itself. A few grams of concentrate running as high as 4 pct U3O8 were recovered from the conditioner when Midnight ore containing less than 0.2 pct U3O8 was treated. In the examples given in Table I this conditioner concentrate is calculated as part of the total concentrate. The authors have not yet fully explored the possi-

Jan 1, 1960

By S. T. Wlodek

The scale md subscale reaction products were identified and their rates of formation were studied in air over the range 1600" to 2000°F (871 " to 1149°C) for periods of up to 400 hr and for hoth the solution-annealed and aged conditions. The effect of prior sltrface preparation on suhscale oxidation was also studied The general oxidation behavior of both Ni-Cr-Mo-Al-Ti type alloys was similar. A surface film of a, Al2O3, forms immediately on exposure Subsequent oxidation continued at a linear rate (QL = 55 * 5 kcal per mole) as colonies of Cr2O3 nucleated at the A12O3/gas interface Further oxidation proceeded at a paraholic rate zvhiclz could he fitted to two successive rate constants. During paraholic oxidation, and depending on temperature, the scale consisted of Cr2O3, NiCr2O4 , and TiO2 with traces of NiO. In the case of Rene 41, the activation energy of both paraholic processes was 66 * 3 kcal per mole suggesting that diffusion of cations tlzrozrgh Cr2O3 was the rate -determining process. An unusual decrease in the oxidation of Udimet 700 at 1900°F where a spinel of Ni(A1,Crh0, zuas the predominant reaction product prevented the accurate assignment of activation energies for this composition. In both alloys internal oxidation of Al2O3 commenced shortly after parabolic scaling was observed. Prolonged exposure prod7tced intemal oxidation of TiN, and in Udimet 700 a complex Mo-Ni nitride was also found. At 1900oF, the subscale reactions in Udimet 700 undergo an inversion which parallels the decrease in surface oxidation; internal oxidation ceases hut is replaced by the formation of "spherodized" 3.' colonies. Surface-preparation techniqtles which introduce appreciable working, such as coarse surface grinding or grit blasting. increase the amount of alloy depletion and internal oxidation in Reni 41. The reverse is true of Udimet 700 for which electropolished or mechanically polished specimens show much more subscale oxidation than strongly worked stirfaces. The strongest commercial nickel-base alloys presently available are generic to the Ni-Cr-Mo-A1-Ti base which exploits the precipitation of Ni3(A1,Ti) as the main strengthening mechanism, while relying on solid-solution strengthening by molybdenum and chromium reinforced by the pre- cipitation of carbides to attain maximum properties. This study characterizes the oxidation behavior of Rene 41, the strongest alloy of the Ni-Cr-A1-Ti type commercially available in sheet form, and Udimet 700, whose higher aluminum and titanium content allows it to exhibit one of the more attractive combinations of high-temperature properties available in a wrought product. The scaling processes of complex, type nickel-base alloys have received relatively little attention. Malamand and vidal as well as Poulignier et al.2'3 have determined the composition gradients across the metal/oxide interface produced by high-temperature oxidation and considered the effect of surface perature, Limited weight-gain data has also been published by Fere 5 for alloys of this type and Radavich6 has identified the reaction products on Udimet 500 and Inco 702 after oxidation at 1832°F. Reference can, of course, be made to the excellent reviews of Kubaschewski and Hopkins7 or Ignatov and Shamgunova8 for a summary of the data available on the oxidation of binary and ternary alloy systems which are related to the more complex alloys considered here. EXPERIMENTAL The analyses of the different commercial heats studied are given in Table I. Using the experimental procedures previously established,9 continuous weight-gain data were obtained on both heats of Rene 41 sheet (A and B) and 150-mil-thick slices of cast Udimet 700. Subscale oxidation reactions were followed by static exposure of cylindrical specimens obtained from swaged Rene 41 (Heat C) and Udimet 700 (Heats E and F). In brief, continuous weight-gain tests were performed on specimens with a surface area of 10 to 12 sq cm. These were abraded through 600 grit Sic paper, electropolished to 2p rms in an electrolyte of 10 pct H2So4 in ethanol, and lightly etched in 10 pct HCl in ethanol before final washing and rinsing in ethanol. All continuous weight-gain data were obtained in dried (-70°F dew point) flowing (1 liter per min) air to an accuracy of +0.1 mg. Subscale oxidation processes were followed by the metallographic examination of 0.5-in-diam by 1.0-in.-long specimens. After an initial center-less grinding, various additional surface treatments were employed to determine the effect of surface preparation on subscale oxidation processes. Before exposure in zirconia crucibles, all samples were lightly etched in 10 pct HCl-ethanol, washed in ethanol, and dried. The depth of internal oxidation was measured to ±0.00025 in. on unetched specimens mounted so as to provide a taper mag-

Jan 1, 1964

By N. H. MacMillan, O. C. Dias

Recent work by Westwood et al. (reviewed in Refs. 1-6) has established that many rocks, minerals, ceramics, and glasses exhibit phenomenologically similar chemomechanical (Rebinder) effects when deformed in different liquid environments, apparently as the result of chemisorption-induced variations in their near-surface flow and flow-dependent fracture behavior. In particular, it appears that there exists an empirical, but apparently general, correlation between the near-surface flow stress of an inorganic nonmetal and its surface charge- namely, that such a solid is hardest at its zero point of charge (i.e., when its zeta potential [ ] = 0) and softens as [ ] increases, regardless of the sign of zeta. Moreover, because near-surface flow and fracture phenomena are two of the important determinants of the rates of machining and comminution processes, both Westwood et al. and others7 have been able to use this so-called "[ ]-correlation" to develop cutting fluids and grinding aids that in many instances have given rise to several fold increases in performance. In addition, Westwood et al. have demonstrated that both aqueous and organic environments can give rise to similar improvements in cutting rate for a given combination of tool and workpiece, provided that both impart the same surface charge to the work- piece (i.e., transfer the same number of electrons to or from its surface). This last finding implies that in any application it should always be possible to find some cutting fluid that is at once effective, cheap, nontoxic, and nonpolluting. Thus, reports of apparently similar environmental influences on the mechanical behavior of diamond,8 certain organic crystals and polymers,9-14 and coa1-15-21 suggest that it is pertinent to ask: (a) whether the [ ]-correlation (or any analogous relationship) extends to coal; and (b), if so, whether this relationship can be used to guide the development of superior aids for grinding coal. Accordingly, correlations have been sought between (1) the zeta potentials, (2) the hardnesses, and (3 and 4) the drilling and grinding characteristics of coals of different rank in different aqueous and organic environments. This paper reports the results of that search.

Jan 1, 1980

By J. Rourke, F. S. Minshall, E. G. Zukas, C. M. Fowler, O&apos

The Hugoniot curves were determined for Fe-Si alloys containing up to 7 wt pct (13 at. pct) Si. The pressure of the transition increased as the silicon content of the alloy increased. Single crystals of 2.9 wt pct Si-Fe were also studied. The pressure of the transition was not dependent on crystallo-graphic orientation. All of the Neumann bands (mechanical twins) were attributable to (112) planes but not all of the {112} planes showed twin markings. A thorough study of the iron Hugoniot (the relationship between specific volume and pressure) under plane wave shock loading revealed a pressure transition at about 130 kbar shock pressure. The results of this investigation were reported by Bancroft, Peterson, and inshall1 in 1956. At the time of this discovery, it was felt that this was probably the a, to y transition normally found in iron and many of its alloys. Subsequently a number of iron alloy systems were surveyed in which the alloying element has a considerable effect on the normal a, to y transformation. The influence of carbon and nickel and/or chromium have already been reported.2,3 At the present time, there appears to be some doubt that this pressure transition is the usual a, to y transition In this study, Fe-Si alloys containing up to 7 wt pct (13 at. pct) Si were chosen for several reasons. To the present, the transition has been found only in iron-base alloys which were originally in the a, phase (bcc). Secondly, the y loop at atmospheric pressure extends to only about 2.5 wt pct Si. If the transition were a, to y, then one might expect a rather drastic pressure effect for alloys containing more than 2.5 wt pct Si. Finally, single crystals of Fe-Si alloys large enough for shock loading studies are readily available thereby making it quite easy to determine the effect of crystal orientation on the transition pressure and on the twinning behavior of the alloy. EXPERIMENTAL PROCEDURE Fe-Si alloys containing up to 7 wt pct Si were produced by normal vacuum casting procedures. Single crystals of Fe-2.9 wt pct Si were purchased from Monocrystals Co., Cleveland, Ohio. The orientations of these crystals were determined and samples cut so that the shock wave would be parallel (to within 1.5 deg) to either the (loo), (Ill), or (112) principal orientations. Three distinct experimental testing techniques were used. First, the pin technique, described elsewhere,4 was used to determine the transition pressure for the polycrystalline alloys as well as for the (111) and (112) orientations of the 2.9 wt pct Si single crystals. Secondly, the recovery studies, described in detail in an earlier paper,2 were used for determining the effect of alloy composition and crystal orientation on the plastic II compression-plastic I rarefaction interaction zone for several specific shock pressures. Finally, measurements of pressures above the two-wave threshold were made on the polycrystalline alloys so that more complete Hugoniot curves could be constructed for this alloy system. The optical techniques described by Rice et al.5 were used to measure the shock and free surface velocities of the samples from which the Hugoniot data were obtained. This method is applicable only in the single wave region, since velocities are obtained from the measured total transit times of the disturbances through measured sample thicknesses.

Jan 1, 1963

Frank Firmstone was born Aug. 29, 1846, at Glendon Iron Works, near Easton, Pa., the residence of his father, William Firmstone, one of the pioneers of the anthracite-iron business. After preliminary school education at Easton, Pa., he attended the Saunders Military Academy in Philadelphia and subsequently entered the Polytechnic College of Pennsylvania, where he was graduated as Mining Engineer in 1865, at the age of nineteen. In 1865 and 1866, he was employed in railroad surveying. In January, 1867, he became draftsman and in 1869, assistant manager of the Glendon Iron Works, of which his father was manager until his death in 1875, when the son practically succeeded to that position, becoming formally in January, 1877, and remaining until February, 1887, the manager of the works and business agent of the Glendon Iron Company. In February, 1889, he became President of the Cranberry Iron and Coal Company, and held that position until November, 1897. He was a director of the Longdale Iron Company, Longdale, Va., from its organizationin 1870 until its dissolution in 1911. With the termination of this official responsibility, Mr. Firmstone retired from active business, although he continued to maintain an intelligent interest, and to play a helpful part, in the scientific progress of the iron industry, in which he had been a leader.

Jan 1, 1920

By H. A. Wriedt

At 500°C (932°F) the range of y' iron nitride is from 5. 77 + 0.03 wt pct N (in coexistence with a iron) to 5.88 * 0.03 wt pct N (in coexistence with E iron nitride). Stoichiometric "Fe,N" (5.900 wt pct N) is near the upper extreme of possible compositiom. The depe-dence of nitrogen activity (expressed as pnh,/Ph,) on nitrogen content is described satisfactorily by a "Langmuir" isotherm: At even the highest nitrogen concentrations, less than 0.18 pct of' the nitrogen atoms present are impositions of disorder. Past investigations1-4 of the Fe-N system have left only details of the thermodynamic behavior of the y' nitride, "Fe,N9', to be studied. The present investigation was made to establish more precisely than hitherto the limits of composition and the relation between composition and nitrogen activity at 500°C. EXPERIMENTAL TECHNIQUE The compositions of nitrides in equilibrium with various NH, + Hz mixtures at 500°C were determined from the weights gained by 0.02-in.-thick (4.0 to 4.5 g) strips of purified iron* when the nitrides were formed A description of the gas generation and furnace system has been published.5 Cracking and blistering during conversion of the original solid iron at 550°C injected considerable porosity into the strips without causing their disintegration. The time for complete conversion was significantly lowered by periodically reducing partly nitrided specimens in hydrogen and then reexposing them to the nitriding gas. Gas mixtures producing single-phase were used in the equilibrations at 500°C. Equilibrium was regarded as existing when the specimen weight was not detect-ably affected by further exposure to the same conditions. The gas compositions and nitrogen activities at which y' transformed to a iron (lower activity limit) and to E iron nitride (upper activity limit) were redetermined during the investigation. A specimen was equilibrated in an NH, + Hz mixture at 500°C and then exposed to a s1ightly different gas. When equi- librium had been reestablished the gas was again changed slightly. At each stage of this repeated process, while the specimen was reacting with the gas, the variation of its weight with time was observed. The onset of phase transition was marked by an abrupt change in the amount and rate of weight gain or loss. The specimens were weighed outside the furnace, in air and at room temperature, on a balance with 0.05 mg precision. When it was found that the specimens were oxidizing at a significant rate during the weighing, a series of timed weighings was made with each specimen, starting 1 min after its exposure to air. RESULTS AND ANALYSIS The gain in specimen weight from oxidation during weighing was linear in the logarithm of time between 1 min and about 2 hr, Fig. 1, later becoming linear in the cube root of time. In the logarithmic period, nitride specimens oxidized two to three times as fast as

Jan 1, 1970

By Joseph M. Jacisin

Fatigue tests were conducted on 2017-T4 alumium in alloy in an u1lrcthig.h vacuum of 2 x 10-lo Torr and in air. The vatio of vacuum-to-air faligue life for this ~malerial varied Jrom 3.5:1 at a strain of 2.5 X 1O-3 ill. pegr in. to 8:l at a strum of 3.3 x X ill. per 171. Sotlze pvelivtlinary data were also obtained on the faligue life of the alumirnum alloy in a dvy-nitrogen atmosphere. A dark deposit observed on the fracture surfaces of the aiv-tested specimens was identified as oxides of tr~angarzese and magnesium This observalion, and the close correlalion betaveen results obtained in vaCuum and dry-nitrogen environtments, tend to confirm that air stvongly influences the fatigue mechanism by a covrosion process. THE fatigue life of certain metals is known to increase when the atmospheric pressure is reduced. Gough and Sopwith1-2 postulated that this is due to a joint chemical and mechanical process operating in air at the surface of the metal with oxygen and water vapor playing significant roles. Wadsworth and Hutchings3 observed that aluminum is mainly affected by the presence of water vapor. Very little information is available on the fatigue properties of structural aluminum alloys in a vacuum environment. This report describes work performed on 2017-T4 aluminum alloy in an ultrahigh vacuum (2 x 10-loTorr) and in air. Some preliminary data are also presented on the fatigue life of the alloy in a dry-nitrogen environment. 1) EXPERIMENT 1.1) Test Material. The material tested was commerciaT 2017-T4 aluminum alloy which, in addition to aluminum, has an approximate composition of 4 pct Cu, 1 pct Fe, 0.8 pct Si, 0.5 pct Mg, 0.5 pct Mn, plus smaller amounts of other elements.* Some typical naturally age to a substantially stable condition. Specimens were then machined from these rods and ground to a No. 8 microfinish. In order to minimize variation in material characteristics, specimens were made from rods procured from the same lot. 1.2) Apparatus. The apparatus and test specimen used in the fatigue tests are shown in Fig. 1. The device utilized a single-cantilever beam with rotating-bending loading. Bending stress was applied to the fatigue test specimen by placing a spacer beneath the bearing support, thereby providing a constant deflec-

Jan 1, 1968

By H. F. Bishop, F. A. Brandt, W. S. Pellini

M. S. Fisher and D. R. F. West (Imperial College of Science and Technology, London, England)—It may be of value to compare certain features of the results recorded in this very interesting paper with those of an investigation11 involving determinations of temperature gradients and rates of solidification of steel blocks of 3 in. sq section, cast horizontally in sand molds, some of which contained chills. Castings in plain carbon steels containing up to 0.8 pct C were made and, throughout this range of compositions, both inverse-rate and direct cooling curves, obtained from thermocouples placed within the mold cavity, showed a major arrest, the temperature of which was taken as the "effective liquidus" for the particular steel in question, solidifying under the conditions of the investigation. At the completion of the arrest, the curves showed a comparatively rapid de- crease in temperature. Some of the steels investigated lay within the peritectic region, and a second arrest at 1485°C was detected. In Fig. 15, which shows the effective liquidus temperatures, the limit of the 8 + liquid field has been placed at approximately 0.5 pct C. In inverse-rate curves corresponding to the thermal center of each casting, there was always a discontinuity, viz: an abrupt change of slope, at a temperature about 10 to 20°C below the "liquidus arrest," after which there seemed to be no significant irregularity in the rate of cooling. Curves corresponding to other positions in the casting generally showed some irregularities below the main arrest, probably as a result of heat flow from the solidifying interior. Even the reproducible discontinuity in the curves for the central positions appeared to have no theoretical or practical significance, though it probably corresponded to a stage in the solidification process at which only a relatively small amount of interdendritic liquid remained. Its temperature, rela-

Jan 1, 1953

By Elmars Ence, Harold Margolin

The Ti-Fe and Ti-Fe-0 systems were re-examined because of the controversy regarding the existence of Ti2Fe, and to consider all available data points to the existence of Ti,Fe. The Ti-Fe-0 system contains two ternary compounds: E, corresponding to Ti2Fe; and y. SEVERAL authors have investigated the constitution of titanium-rich alloys of the Ti-Fe system. The most extensive study of titanium-rich portions of the Ti-Fe system was by Van Thyne, Kessler, and Hansen,' who investigated this system up to 50 pet Fe and used the highest purity materials available for their alloy preparation (iodide titanium was used for alloys up to 20 pet Fe). According to Van Thyne et al., phase relationships in the region of investigation are governed by phases a,ß, and TiFe. No evidence of an intermetallic compound Ti,Fe was found. although earlier. works by Laves and Wallbaum,' and Duwez and Taylor' reported its existence. Rostoker's study on the occurrence of TilX phases" confirmed the findings of Van Thyne et al. Rostoker proposed that the compound Ti Fe found by Duwez does not exist but is actually a ternary compound, Ti1Fe3O, originated by inadvertent oxygen contamination. The partial isothermal section of the ternary Ti-Fe-0 system as reported by Rostoker' seems to confirm this explanation. In the course of phase diagram work conducted at New York University, however, certain irregularities were observed to be associated with ternary systems of the type Ti-Fe-X. The ternary phase 6, observed in the systems Ti-Fe-Mo' and Ti-Fe-V." was found to be structurally identical to the com-pound Ti2Fe as reported by Duwez and Taylor, and to Rostoker's compound Ti1,Fe2O. Since the amount of oxygen possibly present in the Ti-Fe-Mo and Ti-Fe-V systems could not account for the observed amounts of the compound, it appears that the d phase in these systems is not Ti,Fe,O. On the other hand, considering the amounts of the 6 phase, particularly in the Ti-Fe-Mo system, the location of the phase was uncertain. It was felt that the introduction of the Ti2Fe phase would alleviate some of the inconsistencies of the two systems. Because of the uncertainties relating to the phase Ti2Fe, or Ti1Fe2O, it appeared worthwhile to re-examine the Ti-Fe and Ti-Fe-O systems in the vicinity of these compounds with highly sensitive metallographic techniques and with X-ray methods. Experimental Procedure Alloy Preparation—For the study of the binary system four alloys were prepared, containing 26.9 (30 wt pct), 34.0 (37.5 wt pet), 41.2 (45 wt pet), and 56.3 (60 wt pet) atomic pet Fe, and for the ternary Ti-Fe-O system 18 alloys were prepared in the composition range of 1.6 to 16.9 atomic pet 0 and 24.3 to 55.7 atomic pet Fe. The materials used for the Ti-Fe alloys were iodide titanium (99.98 pet Ti, 0.002 pet 0) and Ferro-vac-E iron (99.95 pet Fe, 0.0052 to 0.0072 pet 0). For the Ti-Fe-O study the materials used were sponge titanium containing less than 0.06 pet 0, Ferrovnc-E iron, and Baker's analyzed TiO2. The nominal weight and atomic percentages of the ternary alloys prepared are shown in Table I. Melting—Charges of 10 to 15 g were melted in a nonconsumable arc furnace in argon atmosphere according to the technique described elsewhere.'" Since there was practically no weight loss through the various stages of melting and oxygen losses have not been observed previously, it appeared justifiable to use nominal composition for interpretation of data. Iodide titanium control buttons, of the same mass as the Ti-Fe charges, and melted under the same conditions, were used to check hardness pickup during melting. A hardness increase of 2 to 3 Vhn was found. Heat Treatment—The specimens were annealed in quartz capsules under argon. To avoid contact between the specimen and capsule material all specimens were wrapped in titanium sheet. The annealing times are given in Table 11. The attain-

Jan 1, 1957