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By Henry Emmett Gross

Two types of decline curves are considered and their applications are discussed. The first is the well-known semilogarithmic decline curve having the rate of production plotted on the logarithmic scale and the time on the horizontal scale. The other curve is the percentage of oil in the fluid versus cumulative production, and it is plotted on Cartesian coordinate paper. These curves are illustrated by carefully and adequately labeled graphs. Where conditions permit application of both types of curves for rationally determining the reserves of a well, both should be applied and the most conservative reserve should be chosen. Formulas are given for determining the economic limits. For a semi-l~~arithmic~decline curve the formula is: A = B X C X D X E X F or B = A/C ? D X E X F A = total monthly operating cost (average of past year), B = economic limit in barrels of oil per day, C = days in an average month = 30.4, D = market price of crude per barrel, E = 1-royalty, F = 1-gross production tax, G = water production in barrels per day at the economic limit, H =per cent oil in fluid at economic limit. The economic limit for a per cent oil in the fluid curve is: H = B/B+G X 100 The semilogarithmic decline curve is treated first. Straight-line extrapolations on semilogarithmic paper follow the compound interest compound discount law, hence the ensuing formulas derived from this law may be used in computing reserves for such extrapolations: [1___1/(1+Y)]

Jan 1, 1939

By A. J. Phillips, C. G. Grant, Wm. B. Price

Admiralty nickel is a new corrosion-resisting and heat-resisting white metal alloy composed of 70 per cent. copper, 29 per cent. nickel and 1 per cent. tin. It has been given the trade name "Adnic." In 1924, Wm. B. Price' described this alloy and its successful use as a diaphragm metal. The physical properties of Adnic at ordinary and elevated temperatures were given in Mining & Metallury.~ A patent3 was granted on Adnic, April 28, 1925. Work was first started on this alloy during December, 1921. An investigation of the patent situation in this country and abroad, and also a search of the literature, did not reveal any work on the ternary diagram, copper-nickel-tin; and the only wrought copper-nickel-tin alloy found was that known as "Newloy," composed of copper, 64 per cent.; nickel, 35 per cent.; tin, 1 per cent. This was being manufactured and sold by Wm. Gallimorr & Sons, Ltd., Sheffield, England, for unplated spoon and fork stock, and first came to our attention in January, 1922. The preliminary work in connection with the development of Adnic was started by casting four binary copper-nickel alloys of the compositions shown in Table 1. Various a~ilounts of tin were added to each of these mixtures, to produce the series of ternary copper-nickel-tin alloys also given in Table 1. A 200-gm. sample of each of these was cast by iiielting in a clay graphite crucible and allowing the melt to slowly cool with the furnace. A longitudinal section from each of thcsc castings was polished and etched for examination. The castings were not homogenrous solid solutions, but showed the usual cored structure associated with cast alloys. Howcvrr, frorn an exarrlination of these sections we roughly determined

The First Conference of the Powder Metallurgy Committee convened in the East Foyer of the Hotel Waldorf-Astoria, New York City, at 9:45 a.m., on Feb. 21, 1944, Mr. John Wulff, General Chairman, presiding. THE CHAIRMAN.-In behalf of the American Institute of Mining and Metallurgical Engineers I welcome all members and guests to this conference on Powder Metallurgy. We hope that this meeting will give expert and novice in the field a chance for discussion. Unfortunately, the subject has been overemphasized by some, and, of late, severely criticized by others. We have here today powder producers, fabricators, and engineers of different viewpoints, who can make the meeting a success. Such success depends not only on the caliber of the papers presented but more so on the discussion. To give you time for a free exchange of views, the papers have been shortened purposely. With the hope that you will all benefit by this conference, I shall turn the meeting over to the Chairmen of the morning session, Mr. Roland P. Koehring, of Moraine Products Division of General Motors, and Dr. R. K. Waring, of the New Jersey Zinc Company. SESSION ON DESIGN FACTORS IN POWDER METALLURGY R. P. Koehring and R. K. Waring presiding The opening paper of the session was presented by Mr. Fred P. Peters, as follows:

Jan 1, 1945

By L. D. Ricketts

' In recent years the metallurgical field of the copper industry has expanded greatly, the copper ores have become lean add diverse in charactcr, and we are obliged to treat such ores on a very large scale. On the commercial side, the operating and consulting staffs of the great mining companies have been enlarged and organized, and no great capital expenditure is decided upon until it has been investigated and recommended by a highly organized force of specialists as a committee. I believe that in the scientific field and in the most valuable proceedings of our -various societies the old idea of one-man point of view and one-man treatment of principle and detail together has been splendidly developed and should continue, but for the advancement of our art we should deliberately discuss subjects among ourselves in order to do away with the idiosyncrasies of the individual and to gain a composite view reprcscnting the best thoughts of many men. In the development of new ideas leading to the introduction of new methods, the societies could enlarge their present great field of usefulness if such discussion be had, and in my opinion further great good could be done if a number of men of different qualifications and experience would join in preparing a joint book, each dealing with his particular problem, but consulting the other men. In this way individualism would be preserved and various processes would be described, and if properly reviewed the paper would be palpably capable of analysis, and the student would have at his command the associated efforts of a group of qualified engineers. I have neither the time nor the qualifications to make an investigation and study in detail of hydro-metallurgical processes, but for some years I have foreseen the development of such processes, and I have a deep interest in the subject and have given some of its phases careful consideration from a long-distance viewpoint. I have assisted in directing many experiments and in reviewing the merits of many processes, and am glad to make some introductory remarks with the understanding that other gentlemen present will freely and candidly enter into the discussion and help to fill out the few bare bones that I can uncover.

Jan 1, 1916

By R. Maddin, C. H. Mathewson, W. R. Hibbard

Recent publicationsl.2 establishing the presence of cross-slip in strained metallic single crystals oriented wholly within the area of single slip as predicted from the generalizations of Taylor and Elam3 described these markings as they appeared during the initial stages of the deformation process. At that time, the plane having a common glide direction with the primary slipping plane was reported as the cross-slip plane although the specific direction was not confirmed. Consequently, in continuation of the research, it seemed advisable to investigate the micro-graphic appearance of cross-slip together with the Laue back-reflection X ray analysis and stress-strain data during the later stages of the deformation process. Accordingly, a single crystal of brass (72.75 pct Cu, 0.01 pct Fe, 0.01 pct Pb, 27.23 pct Zn) was polished mechanically and repolished electrolytically after the manner described in the earlier paper.' Three pairs of flat surfaces, parallel to the specimen axis, and (1) perpendicular to the plane containing the pole of the primary glide plane and the specimen axis, (2) perpendicular to the plane containing the pole of the cross-slip plane and the specimen axis, and (3) perpendicular to the plane containing the slip direction and the specimen axis, were polished mechanically and repolished electrolytically, resulting in a final minimum gauge diameter of 0.4864 in. in a gauge length of 3.36 in. The specimen was elongated in tension and load-extension readings were taken following the method described in the initial investigation.' Observed reorientations were obtained from a series of Laue back-reflection photograms at the center and ends of the gauge length and at various positions around the circumference of the specimen. These were interpreted after the manner of A. B. Greninger.4 Cross-slip (Fig 1 and 2) was found with the first appearance of the primary slip clusters and usually joined members of these clusters. In addition, a third set of entirely different markings (Fig 3) could be noted. The displacement of this third set by the primary slip lines was measured as 8300 at. diam (3.04 microns). Since the specimen was carefully observed at high magnifications before any deformation and no markings of any type could be noted, it would appear that this third set was formed during the deformation process prior to the initiation of classical primary slip. Additional extensions produced no unusual change in the appearance of either cross-slip or the third set of markings. The number of lines increased with increasing elongation and appeared, generally, in areas where earlier markings were present. The continuity of the clusters of cross-slip lines in Fig 4, 5 and 6 illustrates that they are neither noticeably displaced by nor do they displace the primary lines at this stage. In Fig 7, cross-slip appears in a long narrow localized band approximately 45 degrees from the stress axis. This somewhat resembles a twin band except for the lack of a sharp boundary. After a shear of 0.257, suffcient additional glide occurred on the cross-slip plane to displace the primary slip lines (Fig 8). Generally, where a large number of cross-slip lines could be observed in an area on one flat surface, few cross-slip lines appeared on the diametrically opposite position on the parallel flat (Fig 9). These, of course, were not matched observations on the same glide ellipses. It was extremely difficult to make such comparisons. The third set of markings (Fig 10) was extensively displaced by glide on the primary slip planes. A plot of the width of primary slip clusters versus their displacement of the third set of lines is shown in Fig 11. The slope and the linearity of the plot suggest that each primary glide plane slips to a constant maximum value of shear before further slip is transferred to another plane. A shear value of 0.28 was determined in this case. Heidenreich5 has presented a similar schematic representation of glide for aluminum. After the specimen had attained an elongation of 51.8 pct, corresponding to a shear of 0.973, cross-slip appeared very prominently in certain areas as shown in Fig 12, yet at diametrically opposite positions very little cross-slip could be noted, Fig 13. Classical conjugate slip was found at this advanced stage in the deformation, Fig 14, which corresponds to the axial location shown at 12 in Fig 15. It should be noted that cross-slip occurs within the conjugate slip clusters and on the same plane as the cross-slip associated with the closely spaced primary lines which constitute a background in less distinct focus. The third set of markings noted at all stages in the deformation of the

Jan 1, 1950

A SPRING meeting is to be held at Cleveland this month under the joint auspices of the Iron and Steel Committee and the Ohio Section with the cooperation of the neighboring sections in Pennsyl-vania, Illinois, and the other States of the Great Lakes region. The discussions will be focused on just one subject, that of manganese, but will cover that thor- oughly as is indicated by the following list of papers. TECHNICAL PROGRAM Some Political Aspects of the World Manganese Situa-tion. By C. K. Leith, Professor of Geology, Uni-versity of Wisconsin, Madison, Wis. Manganese Resources in Relation to Domestic Con-sumption. By J. V. W. Reynders, Consulting En-gineer, New York, N. Y. Manganese Deposits of the' Gold Coast, Africa. By Sir Arthur E. Kitson, Director of the Geological Sur-vey of the Gold Coast, London; with Notes on the Petrology of Certain Associated Manganese Silicate-bearing Rocks. By Maj. N. R. Junner. Reserves of Lake Superior Manganiferous Iron Ores. By Carl Zapffe, Manager, iron ore properties, North-ern Pacific Railway Co., Brainerd, Minn. Iron Manganese Alloys Low in Carbon. By. Sir Robert Hadfield, Hadfields, Ltd., London. Manganese in Non-ferrous Alloys. By M. G. Corson, Consulting Engineer, New York, N. Y. Importance of Manganese in the Steel Industry. By H. M. Boylston, Professor of Metallurgy, Case School of Applied Science, Cleveland, Ohio. Minnesota Manganiferous Iron Ore in Relation to the Iron and Steel Industry. By T. L. Joseph, E. P. Barnett and C. E. Wood of the North Central Min-ing, Experiment Station, U. S. Bureau of Mines, Minneapolis, Minn. Representatives of the leading steel companies, the Army, the Navy, the Geological Survey, Bureau of Mines, and leading technical societies will be present and a lively discussion of the various papers is already assured. Nearly 14 pounds of manganese is needed for every ton of steel made. Estimates indicate that the total reserves of ore in this country suitable for making ferro would hardly supply domestic requirements for ten years, even if it could all be mined in that time. The grade of ore called for by present practice must come from abroad. The present tariff policy of this country is stated to cost industry $8,000,000 in order to force production of manganese ore to the extent of $600,000. What is the wise thing to do? Should a stock be accumulated? If so, how? Is it feasible to change practice and use low-grade ore or to beneficiate the ores of this grade and meet our requirements? What progress is being made in this direction? ,These and similar questions are raised in the various papers that have been submitted and will be open for dis-cussion.

Jan 3, 1927

By G. B. Walker

THE sink-float methods designated by heavy-media separation processes were pioneered by C. Erb Weunsch for the treatment of base metal ores as an improvement over jigs. The work of Weunsch was further developed by Victor Rakowsky and The American Zinc, Lead and Smelting Co. Early in the development of the processes, the inherent unsuitability of galena as the solid constituent of the medium was recognized and ferrous media amenable to magnetic recovery and control were developed. The high efficiency and low cost of magnetic recovery and cleaning of ferrous media regardless of particle size, slime contamination, or surfacial oxidation had led to the adoption of ferrous media by all of the sink-float plants operating under the heavy-media separation processes patents controlled by American Zinc, Lead and Smelting Co. Approximately 2,000,000 tons of base metal and nonmetallic minerals are treated each month by these methods.

Jan 1, 1949

By Joseph W. Richards

This method of briquetting flue-dust, or flue-dust mixed with fine ores, or, in a few exceptional cases, coke-dust, has come into large commercial use in Europe, and a small plant is already in operation in the United States. It promisea to become of such great importance to the iron industry of the United States that the following description will certainly interest the majority of our pig-iron producers. Discovered in 1908, the process Tests upon the observation of Dr. Schumacher that blast-furnace flue-dust, while possessing of itself no binding or cementing properties, acquires strong cementing properties if mixed with a very small amount of certain salt solutions, the amount of which is so small that the resulting cementation appears to be rather by catalytic action of the salts added than by the mass-action of such chemicals. To be more specific, fresh blast-furnace flue-dust mixed with from 5 to 10 per cent. of its weight of magnesium chloride or calcium chloride solution—that is to say, with from 0.25 to 2 per cent. of its weight of magnesium chloride or calcium chloride—acquires the property of setting within a short time, from 15 to 60 min., and forming a hard cemented briquette. Alkaline solutions appear to have no action such as described, and they even interfere, if present, with the action of the magnesium and calcium solutions. When treated in this way the flue-dust briquette sets very hard, apparently from pure excess of cementing- and setting-power. It is, therefore, possible to mix with the flue-dust a considerable proportion of inert ore or like material, which has no setting-power by this process, and thus to make a compound briquette containing large quantities of ore mixed with flue-dust, but in which the flue-dust may be regarded as the cement or binding-material. A particularly strongly cementing flue-

Jan 1, 1913

By A. C. Fieldner

THE total annual energy production from coal, petroleum, natural gas and water power has been increasing at a fairly constant rate during the thirty years ending in 1930. But since 1913 the demand for the competitors of coal has increased at a rate faster than that for coal. During the last twenty years, the curve of coal production has had a generally horizontal trend; in fact, the 1930 production of coal was six per cent less than that of 1913. Economists attribute this loss of demand to greater efficiency in coal utilization and to displacement of coal by oil and natural gas. These two factors are about equally responsible, and it is evident that research has been intimately concerned with both. About sixty per cent of the bituminous coal mined in the United States in 1929 was used for generating steam, either in stationary or locomotive boilers. A decade ago seventy per cent or more was used for this purpose. This change is due largely to tremendous advances in fuel economy.

Jan 1, 1933

By LE B. GRAY

ALL meeting of the Chemical Section, National Safety Council, in Rochester, N. Y., put his hand on at least ten salient points that apply to safety in nearly any laboratory ; these are as follows : 1. Impress your laboratory worker at the start that he is dealing with powerful and dangerous-forces and that every experimental set-up must be studied from the stand- point of its fiber, electrical, explosive, and health hazards.

Jan 1, 1929

By F. N. Lathe

In 1882, The Arizona Copper Co., Ltd., acquired producing copper mines at Metcalf and Morenci (locally called Longfellow). Metcalf is situated a distance of 7 miles, and Morenci a distance of 6 miles from the general office of the company at Clifton, Ariz. A reduction works with five blast furnaces was built in the center of the town of Clifton in 1884 and operated until January, 1914. Concentration of oxidized ores was begun in 1890-1891, in a mill built adjoining the smelter, and id October, 1893, a leaching process was started for treating tailings from the oxide mill. A sulphide concentrator with 300 tons capacity was built at Clifton and started treating chalcocite ores in July, 1896. This was the first mill to treat low-grade copper-siilphide ores successfully. Another concentration mill for sulphide ores was erected at Morenci in 1900. The sulphide mills are now being remodeled to treat ores by concentration and flotation, with a capacity of 4,000 tons at Morenci and 500 tons at Clifton. The leaching plant has not been running since September, 1914. The average yearly production from this company's mines and reduction works from 1885 to date has been: Pounds 10 years ended 1894................................... 6,864,902 10 years ended 1904................................... 20,439,614 10 years ended 1914................................... 32,665,905 Part of year 1915, to Sept. 12........................... 30,206,106 4 months of 1916, to June.............................. 15,964,840 June, 1916........................................... 4,900,000 Construction on a new smelting plant was started in February, 1912, and finished in February, 1914. In the Transactions, vol. 49, E. Horton Jones published "Unit Construction Costs from the New Smelter of the Arizona Copper Co., Ltd.," which fully describes the construction of this plant, with details of costs.

Jan 1, 1917

By E. T. Turkdogan, J. H. Swisher

bi the fivst part of the paper results ave given on the rate of decarburization of Fe-C melts ln CO2-CO atmospheres at 1580°C. The rate -controlling step is believed to he that irvlloluing dissociation of curbotz dioxide on the suvfuce of the melt. 4 genevral reaction mechanistm is poslnlated jor gels-t11eta1 veactions oc-curit~g on the surface of iron coutcotamncited with chemi-sovbed osygesL. Oxygen the present work on decavbuvization of liquid iron and previous studies on the kinetics of nitrogen absorption and desorplion are discussed in terms of the postulated mechanism, ManY of the early studies of rate of decarburization of liquid steel were of an exploratory nature and laboratory exppriments carried out pertained to open-hearth or oxygen steelmaking processes. References to previous work on this subject may be found in a literature survey made by Ward. Using more sophisticated experimental techniques, several investigators have recently studied the kinetics of decarburization of molten Fe-C alloys in oxygen-bearing gases. For example, Baker et al2.' reported their findings on the rate of decarburization of liquid iron, levitated by an electromagnetic field, in carbon dioxide-carbon monoxide-helium atmospheres. In these levitation experiments the samples used were small in size, e.g., -0.6-cm-diam spheres weighing -0.7 g, and the rates were measured for decarburization from about 5 to 1 pct C at 1660°C. The rates obtained under their experimental conditions were considered to be controlled primarily by gaseous diffusion through the boundary layer at the surface of the levitated melt. Parlee and coworkers3 measured the rate of absorption of carbon monoxide in liquid iron. The rates were found to follow first-order reaction kinetics, yielding a reaction velocity or a mass transfer coefficient in the range 0.2 to 0.4 cm per min. The coefficient was found to decrease with increasing carbon content of the melt. These investigators attributed the observed rates to the transfer of carbon or oxygen through the diffusion boundary layer adjacent to the surface of the melt. In the work to be reported in this paper, an attempt has been made to study the kinetics of gas-metal surface reactions involved in the decarburization of liquid iron. EXPERIMENTAL The experiments consisted of melting 80-g samples from an Fe-1 pct C master alloy in an induction furnace and decarburizing in controlled CO2-CO mixtures at 1 atm pressure and 1580°C. The master alloy was prepared by adding graphite to electrolytic "Plastiron" melted in racuo. None of the impurities in the master alloy exceeded 0.005 pct. The reacting gases were dried by passage through columns of anhydrone; in addition, CO2 impurity in carbon monoxide was removed by passage through a column of ascarite. A schematic diagram of the apparatus is shown in Fig. 1. A 1.25-in.-diam recrys-tallized alumina crucible containing the sample was placed inside a 3-in.-diam quartz reaction tube, all of which was surrounded by an induction coil. A 450-kcps induction generator was used as the power source. Water-cooled brass flanges, which contained the gas inlet, gas exit, and sight port, were sealed to the top of the reaction tube with epoxy resin. The reacting gases were metered with capillary flowmeters and passed through a platinum wire-wound alumina preheating tube, 0.25 in. ID and 11 in. long. The gases were preheated to about 1300°C. A disappearing-filament optical pyrometer was used to measure the melt temperature. The pyrometer was initially calibrated against a Pt-6 pct Rh/Pt-30 pct Rh thermocouple. The temperature was controlled to within +10°C by manually adjusting the power input to the induction coil. In a typical experiment, an 80-g sample of the master alloy was melted in a CO2-CO atmosphere having pcO2/pco = 0.02 and flowing at 1 liter per min. A negligible amount of carbon was lost and no significant reduction of alumina from the crucible occurred during melting, e.g., 0.005 pct Al in the metal. After reaching the experimental temperature of 1580°C, the gas composition was changed to that desired for a particular series of decarburization experiments. The duration of the transient period for obtaining the desired gas composition at the surface of the melt was about 20 sec . The flow rate of the reacting gas was maintained at 1 liter per min. After a predetermined reaction time, the power to the furnace was turned off. During freezing, which took about 10 sec, the amount of gas evolution was not sufficient to result in a significant loss of carbon. The samples were analyzed for carbon by combustion and in a few cases they were analyzed for oxygen by the vacuum-fusion method. RESULTS A marked increase in the rate of decarburization of iron with increasing pcO2/pco ratio in the gas stream is demonstrated by the experimental results given in Figs. 2 and 3 for pco2/pco ratios from 0.033 to 4.0. In one series of experiments, denoted by filled triangles in Fig. 2, the reacting gas was diluted with argon (48 vol pct) resulting in a slower rate of decarburization. Samples from two series of experiments with pco2/pco = 0.033 and pco2/pco = 0.10 (with argon dilufion) were analyzed for oxygen. In these Samples the oxygen content increased with reaction time

Jan 1, 1968

By D. J. Schmatz, H. I. Aaronson, H. A. Domian

Diffusion kinetics in disordered hcp Cd-Mg alloys have been investigated by means of the Kirkendall effect and concentration-penetration curves determined with an electron-microprobe analyzer. Self-diffusion coefficients of both species were determined at the three marker compositions obtained, averaging 27.6, 46. 7, and 78.1 at. pct Mg, by means of the Darken analysis. These coefficients were then corrected for the unequal and concentration-dependent partial molar volumes of the two elements with the Balluffi analysis, and for the vacancy flux effect by the Manning analysis. The latter correction reduced the Balluffi correction produced larger changes in the self-diffusiv-ities; neither, however, produced statistically significant changes in the Do's or the H'S. The most striking result of this investigation is that at all three compositions and at all temperatures studied both the uncorrected and corrected self-difjusivities of magnesium are higher than those of cadmium. The Cd-Mg system is the first one found in which the higher melting, lower vapor pressure element diffuses more rapidly. Both an empirical correlation due to Toth and Searcy and considerations of the atomic mechanism of diffusion indicate that this anomaly is probably due to a comparatively low value of the activation energy required for a magnesium atom and a vacancy to exchange sites, perhaps occasioned by the higher compressibility of magnesium atoms. KIRKENDALL effect studies have been previously reported for only two hcp solid solutions: the E phase of the Zn-Cu system1 and the a phase of the Cd-Hg system.' In neither investigation were the marker-movement studies supplemented with the concentration-penetration curve determinations necessary to evaluate self-diffusivities by means of the atano and the Darken analyses. The present program was undertaken to obtain both types of data on a hexagonal solid solution in order to provide more detailed information relevant to the mechanism of diffusion in this type of lattice. The Cd-Mg system was chosen for this study because the disordered solid solution extends across the entire phase diagram at temperatures above 253"c5 and the substantial difference in the melting points of the component pure metals promised that marker movements would occur at reasonably rapid rates should the diffusivities of the two species be as unequal as might be anticipated. The experimental convenience of the relatively low melting points of cad-miun and magnesium and the availability of extensive and accurate activity data6 (required for application of the Darken analysis) were additional reasons for selecting this alloy system. Since the anisotropy of diffusion is not large in either pure cadmium7 or pure magnesium,' the diffusion couples were prepared from polycrystalline components. The presence of a well-defined texture in the couples—the c axis of individual crystals tended to be normal to the diffusion direction— however, provides a fair degree of crystallographic definition to the data obtained. The principal (and entirely unexpected) finding of this investigation, that magnesium, the high-melting low-vapor pressure element, diffuses more rapidly than cadmium, in contradiction to a broad range of results in fcc and bcc alloys, as well as in the previously studied hcp alloys,172 makes the self-diffusivity determinations of immediate interest in understanding the origin of this anomalous result. EXPERIMENTAL PROCEDURE The cadmium (Belmont Smelting and Refining Co.) and magnesium (Dow Chemical Co.) used in this study were both of 99.99 pct purity. Alloys containing 51.0 and 65.6 at. pct Mg were prepared from these materials by melting under a MgC12-base flux in a high-purity graphite crucible. These alloys were subsequently hot-worked and then homogenized in a helium atmosphere at temperatures close to their solidus points. Sandwich-type diffusion couples of the type g/d/g were prepared from the pure metals by solid-state diffusion. Two-piece alloy couples of Mg/65.5 at. pct Mg (Mg/gCd) and Cd/51.0 at. pct Mg (Cd/CdMg) were welded by a liquation technique. The individual components of both types of couple were initially cylinders 1.27 cm in diam and in length; the ends of these cylinders were machined accurately flat and parallel. For both welding techniques, the pure cadmium cylinders and the alloys were chemically polished in a mixture of 40 pct ethyl alcohol, 40 pct hydrogen peroxide (30 pct conc), and 20 pct nitric acid,g while those of pure magnesium were polished in a solution of 10 pct nitric acid in ethyl alcohol.' Immediately afterwards, both metals were rinsed in freshly distilled acetone, and then in similarly purified methanol.' The Mg/Cd/g couples were assembled in a carefully cleaned stainless-steel welding fixture, in which a screw operating through a self-centering arrangement permitted a controlled pressure to be exerted upon a couple prior to welding.'' Tungsten marker wires 0.005 cm in diam were placed at the d:g interfaces of some of these couples, and imbedded in the couples during the application of pressure. As soon as a couple had been assembled, the welding fixture was inserted into a Pyrex capsule containing a packet of zirconium chips at each end. The capsule

Jan 1, 1967

By AIME AIME

COAL occupied a large place in the technical sessions of the Institute at its annual meeting for in addition to three sessions specifically de- voted to coal the two sessions on mine ventilation and the two on ground movement and subsidence, which are reported under their own headings, were primarily concerned with coal. The first session on coal was a joint one with the Iron and Steel Division, on Wednesday afternoon, with F. H. Crockard and J. R. Campbell presiding as joint chairmen and the latter actually officiating. The principal topic of discussion was G. S. Scott's paper "Evaluation of Coal for the Making of Blast- Furnace Coke," which has been published as T. P. 159. The author made a brief statement of its con- tents to start the discussion and the chairman, after briefly reviewing it himself, called on C. A. Meissner to start the discussion. He briefly reviewed the economic factors in the use of coal for coke-making, saying that not only .does the removal of 1 per cent of ash from the coal reduce the cost of pig iron 12 or 13c. per ton, but it also permits coke of satisfactory structures to be made from a coal which otherwise could not be used. He stressed the importance of uniformity in blast-furnace fuel and discussed the benefit of mixing different coals as raw material for the coke oven and cited experience with Illinois coals.

Jan 1, 1929

By A. Bar-Or, G. Hirsch, P. Wynblatt

The rates of nucleation and growth at various temperatures in U-0.45, 1.1, and 1.35 at. pet Cr alloys were determined, providing a qliantitative proo-f that the transformation under study is controlled by nucleation and diffusional growth. The linear relationship, log NV US 1/T2, suggests that the nucleation of the alloys is probably controlled by the classical law of nuclei formation. The established linear relationship, log G us 1/T, in the three alloys suggests that growth in each alloy is controlled by bidimensional nuclei formation. It was established that both the rate of growth and the rale of nucleation are retarded by chromium. Using classical formulae, sApN and sApG (the ß/a apparent interphase energies) were calculated from the nucleation and growth results, respectively. It was found that their values are of the same order of magnitude. However, why sApN is unaffected by the addition of chromium, while sApG increases with it, needs further clarification. In the last few years, an appreciable amount of research has been conducted into the mechanism of the ß —a transformation in uranium and uranium alloys. Recently, Burke1 reviewed the published work concerned with this transformation. He concluded that in dilute uranium alloys it is firmly established that, at high temperatures in the a range, ß decomposes by a diffusional process. However, he based his conclusion either on experiments dealing with the over-all transformation,2 or on qualitative results.3 It was felt that a better insight into the mechanism of transformation could be gained from the quantitative measurements of growth and nucleation rates, which we aimed to carry out in the present work. In a previous work,4 we have shown that a rim of a grains is formed during isothermal transformation at the high a range. The thickening of this rim with time was used for measuring the rate of growth in U-0.45 at. pet Cr.5 This method was also used in the present work for two more alloys. For meas- uring the rate of nucleation, a method of quenching and macroetching was developed to allow differentiation between a grains formed during isothermal transformation at the upper a range and those formed after quenching, Fig. 1. EXPERIMENTAL WORK AND RESULTS The Rate of Nucleation. The measurement of the rate of nucleation was effected by counting the num-

Jan 1, 1965

By Gordon S. Duncan

(New York Meeting, February, 1912 THE U. S. Geological Survey, I believe, has almost completed a study of the Harney Peak quadrangle, preliminary to the publication of a report on that, district. As I was engaged for some months on an investigation of the mode of occurrence of the ore-bearing formation in this area, it has seemed to me timely to make public the results of my study, as a contribution to the consideration of this subject. It seems scarcely necessary to describe the locality and general geology of the Black hills of South Dakota, for since 1846 many have contributed information concerning this region, some of the reports bearing such well-known names as those of Walter P. Jenney, Henry Newton, S. F. Emmons, and C. R. Van Hise, while we have only to glance at Bulletin No. 4 of the South Dakota School of Mines, in which Prof. C. C. O'Harra, of that institution, has given us a bibliography of contributions to the geography and geology of the section, to find that other well-known men have studied the district, and have given us the benefit of their researches. The U. S. Geological Survey has made geological maps of nearly the whole of the Black hills, the only quadrangle yet to be completed being, as stated, the Harney Peak district. During the late summer and autnmn of 1910, it was my lot to examine and report. on a considerable area in this neighborhood, which once had been prospected, and in some cases exploited, for tin. This paper gives an account of certain geological phenomena, noted at that time, which greatly influenced my conclnsions. The predominating formation of the district is pre-Cambrian, represented by a highly-cleaved mica-schist, usually very garnetiferous, and sometimes hornblendic. Rising like an island from the surrounding schist is a large mass of granite, known as

Jul 1, 1912

By Richard H. Jahns

GRANITIC pegmatite deposits are the chief source of commercial feldspar, sheet mica, beryllium, tantalum-columbium, and lithium minerals, and certain types of kaolin. They also have yielded significant quantities of cassiterite, gems, scrap mica, molybdenite, tungsten minerals, uranium-thorium and rare-earth minerals, and zircon, either directly or as the sources of placer deposits. The output from pegmatite mines in the United States is small as compared to other mineral products in terms of bulk or value, and much of it comprises minor metals and nonmetals. Nevertheless, pegmatite minerals play a vital part in domestic industrial economy, particularly in the ceramic and electrical industries. Numerous special purpose uses also are important, even though they require small quantities of raw materials. Never was United States dependence upon pegmatite mining more clearly emphasized than during World War 11, when greatly expanded demands and uncertainties of foreign sources of supply caused much concern. Such commodities as beryl, tantalite, and sheet muscovite remained high on the critical list for months at a time, and for some minerals there was a real struggle to achieve and maintain a favorable ratio of supply to demand. Satisfactory stock piles of certain sizes and qualities of sheet mica, for example, were not built up until late in 1944, when wartime requirements already had begun to level off or even to decrease. Production of all the strategic pegmatite minerals from domestic deposits during World War I1 constituted only 10 pct or less of the total domestic consumption of these minerals, but the importance of this contribution should not be minimized. Domestic production often represented the difference between increase and further reduction of existing stocks of commodities already in seriously short supply, and in the early stages of the war it was the only assured source if imports were cut off. During the recent war period, the U. S. Geological Survey carried on a program of pegmatite studies in the New England and Southeastern States, in the Black Hills area of South Dakota, in the Rocky Mountain region of Wyoming, Colorado, and New Mexico, and in various parts of Washington, Idaho, Utah, Nevada, Arizona, and California as shown in Fig. 1. Several papers and reports already have appeared as an outgrowth of this work,'-= and others are in preparation. This paper outlines some results of data obtained by the writer during the period 1942 to 1946, when he was engaged in studies of pegmatites in the Southeastern, Southwestern, and Rocky Mountain States. Beryllium Minerals Beryl is the present commercial source of beryllium metal and beryllium compounds, which are used in ceramics, in the preparation of X-ray tubes and fluorescent lamps and screens, in special processes of paint and textile manufacture, and in the optical systems of some electrical instruments. The metal also is used in nuclear physics, chiefly as a source of neutrons. Beryllium is alloyed with aluminum for certain light-metal uses and is a constituent of some nickel and iron alloys. Currently the chief demand, however, is for copper-base alloys, which are exceptionally resistant to fatigue and wear, are responsive to hardening treatments after

Jan 1, 1952

By T. Toda, R. Maddin

A study has been made of the microstructure and mechanical properties of splat-cooled aluminum-base gold alloys with gold concentration from 0.25 to 5.0 wt pct. These alloys have been quenched from the liquid state by a torsion-catapult technique, which has made it possible to pepare specimens suitable for mechanical property measwements. From the electron micrographs it has been shown that the solid solubility of gold in aluminum can be extended to 2.5 wt pct (0.35 at. pct) by splat-cooling, while the maximum equilibrium solubility is known to be less than 0.3 wt pct (0.04 at. pct). The very fine grain size (several tenths of a micron), the extended solid solubility, and the fine dispersion of a second phase (AuAl2) contribute concurrently to a substantial strengthening effect. In Al-5 wt pct Au splat-cooled specimens of less than 50 thickness, the yield strength is 17 kg per sq mm or 6 times as large as the strength of bulk specimens. For the Al-1.0 to 2.5 wt pct Au solid solution obtained by splat-cooling, the yield strength reaches 7.5 kg per sq mm after an aging treatment (for 10 hr at 200°C), while it is 3.7 kg per sq mm for the corresponding bulk specimens. A great deal of research has been done in recent years on the structure and the properties of metals and alloys rapidly quenched from the liquid state.' The term "splat-cool" has been used with the meaning of a rapid quenching from the liquid state., The splat-cooling techniques have produced large numbers of new structures, which are expressed in terms of metastable phases,3 concentrated solid solutions,4 amorphous phases,5'6 new phases,7 and so forth. Nearly all previous studies have concentrated on the physical properties; i.e., crystallography, structure, electrical resistivity, magnetism, and so forth, of the splat-cooled metals and alloys. The mechanical strength of splat-cooled metals and alloys has hardly been investigated except for some recent work by MOSS' on A1-V alloys. The principle common to all experimental techniques developed to obtain very rapid quenching rates is based on the heat transfer by conduction. Liquid must be in good thermal contact with a substrate of high heat conductivity. Both of the published devices known as the "gun" and the "piston and anvil" techniques suffer from certain shortcomings. For example, the specimen obtained by the gun technique is very small and flaky, and hence inadequate for mechanical properties measurements. On the other hand if the material is forced to yield a continuous speci- men by the piston and anvil technique, it is probable that some plastic deformation occurs during the quench. A novel method for rapid quenching of a liquid metal or alloy, the "torsion-catapult", has been devised by Roberge and Herman9 at the University of Pennsylvania. In the apparatus the melt is thrown out of a curved furnace by a catapult and impinges on a copper substrate. The apparatus has the advantage of producing a continuous foil which is relatively large in size and of a quality suitable for the measurements of mechanical properties. The quenching rate is estimated to be of the order of l05 to l06 ºC per sec, (comparable to rates achieved by the piston and anvil technique). In selecting an alloy to be studied we were made aware of the fact that gold was believed to be "insoluble" in in and consequently age hardening in the A1-Au system appeared to be interesting. Quite recently Heirnendahl13-15 revealed that the solid solubility, as determined by transmission electron microscopy, was 0.3 wt pct Au at 640°C and 0.25 wt pct Au at 600°C, decreasing with decreasing temperature. In an A1-0.2 pct Au alloy after quenching from a solution treating temperature of 600°C the yield stress was 2 kg per sq mm, and it increased up to 6 kg per sq mm after aging for 1 to 10 hr at 200°C. The precipitation occurred in the form of platelike particles mainly on (100) matrix planes. The intermediate phase n', the equilibrium phase n (AuAl2), and lattice relationships between both precipitates and the matrix were also investigated by electron microscopy. One of the purposes of the present research is to determine whether or not the solid solubility in this system, in which gold has a very small solubility in

Jan 1, 1970

By R. W. Diamond

Low-grade ores can be designated by two main classifications: (1) simple low-grade ores, and (2) complex low-grade ores. As a rule the first type has a relatively small metal content, although low- grade iron ores contain a rather high percentage of metal. As the simple type is the one that is ordinarily in mind when the term "low-grade ore" is used, the paper will be devoted mainly to ores in this general category. Cheap treatment is the prime requirement in utilizing low-grade ores of the simple type, although in some cases the value of nonmetallic by-products, such as limestone for fer- tilizer and silica for flux, allows a little more lati- tude than in the usual situation. When the costs are divided under the three headings-mining, milling, and smelting-it is apparent that the last group will not constitute an important factor as a rule because the high concentrating ratio makes the smelting cost per ton of ore fairly low.

Jan 1, 1949

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