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By E. J. KENNEDY

FEBRUARY 15-18 will be the outstanding dates of the month for members of the A. I. M. E., for then the 141st Meeting of the Institute is to be held in the Engineering Societies Building, at New York. What with 41 technical sessions, the Annual Business Meeting at 4 o'clock Tuesday afternoon,, two sessions of the Section and Division delegates, minor committee meetings, and the many luncheons and dinners, the Dinner-Smoker, Informal Dance, President's Reception and the Dinner-Dance, the opportunity will be limited to do- more-than cast sheep's eyes at New York's other multitudinous attrac¬tions until the meeting is over. The technical program is diverse but well organized. The sessions are almost equally divided among the four days, with ten on Monday, Tuesday, and Wednesday, and 11 on Thursday. The meeting opens Monday morning with registration. Be sure to attend to this detail. Failure to do so may have its repercussions at the meeting and throughout the year.

Jan 1, 1932

By A. Yazan, M. Sagheer

To meet the demands of the planned development of Turkish steel industry an Iron ore processing plant is under construction at Divrigi, Anatolia and is planned to be commissioned mid of 1978. The plant has been designed for an annual capacity of 4 million tons of crushed magnetitic ore. About 1.9 million tons of coarse concentrate of 25-2 mm size and 1.3 million tons of pellet feed concentrate will be produced by wet screening, dry magnetic concentration of coarse size fractions and wet magnetic concentration of fine size fraction. The fine magnetic concentrate will be reground and filtered to prepare the feed for the pelletizing plant.

Jan 1, 1978

By Robert E. Wilson

TO show the vital importance of our future oil supplies to our economy, I will merely point out that this country, with something like 15 per cent of the world's land area and something like 7 per cent of the world's population normally uses between 65 and 70 per cent of the motor vehicles of the world, between 65 and 70 per cent of the world's rubber, and produces and refines between 65 and 70 per cent of the world's petroleum. Despite all the arguments as to which is cause and which is effect, all will agree that all three of these important industries are mutually dependent. If we had not been able to produce 65 or 70 per cent of the world's oil in this country we would not have the degree of mechanization, or the efficiency of transportation, or the high industrialization that we enjoy. Furthermore, the fact that oil has been plentiful and cheap has had a tremendous effect on all the things in which we as engineers are interested. For that reason, if for no other, it is well to look ahead to see what the outlook is for the near and far-distant future.

Jan 1, 1945

By Julian E. Tobey

A MEMORABLE year has just passed in the field of coal utilization. Because of the war, oil conversions in industrial, commercial, and domestic installations have been made to the equivalent of 20,000,000 tons of coal. The war emergency has resulted in a great shifting of various types of coals to various markets. Huge tonnages of metallurgical-quality coals have been withdrawn from steam and domestic business and sent into the iron and steel industries. Marginal coals have replaced these coals in the steam and domestic field.

Jan 1, 1944

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 W. D. Forgeng, B. F. Decker

IT has been known for almost a century' that silicon and nitrogen combine when heated to a high temperature. Three nitrides have been reported, SiN, Si3N,, and Si,N, containing 33.3, 40.0 and 42.9 pct nitrogen by weight, respectively. The existence of SisN, is well established but that of Si,N, and SiN is doubtful. The first systematic study of the reaction between silicon and nitrogen was made in 1910 by Weiss and Engelhart" who determined the rate at which silicon absorbed nitrogen at temperatures from 1250°C to

Jan 1, 1959

By A. J. M. Ross, R. G. Wayland

The Homestake mine is situated in Whitewood mining district, in the northern Black Hills of South Dakota, in the city of Lead, Lawrence County. The entire property, comprising 557 lode claims with a total area of 3343 acres, is held under United States Patent. The older claims were 300 by 1500 ft. under local regulations, the newer ones 600 by 1500 ft. The Homestake was discovered April 9, 1876, by Moses and Fred Manuel, and Jake Harney, who were drawn into the northern hills, from the Custer placer district, by news of the discovery of rich placer deposits in Deadwood Gulch. They located a number of additional lode claims and, in a short time, the whole country was covered with locations. The Manuel brothers built an arrastre the following winter and took out $5000. The next year the Homestake lode was sold to Senator George Hearst and associates, who organized the Homestake Mining Co. Other companies were formed to exploit other groups of claims and at one time fivc companies were operating on this deposit, the Father DeSmet, the Dead-wood-Terra, the Caledonia, the Highland, and the Homestake Mining Co. These companies, however, have been merged into the Homestake Mining Company. The first stamp mill, known as the "Eighty Mill," commenced operation on July 12, 1878, and production has been nearly continuous since that time. Geology The orebodies of the Homestake are found in an intensely folded and altered bed of dolomitic limestone occurring in a series of ancient rocks believed to be of Archean age, belonging to the Keewatin series. The Keewatin series is estimated to be 20,000 ft. thick and is made up essentially of quartz mica schists, garnet schists, quartzites, slates, and some green schists, probably derived from basic igneous rocks. The dolomitic limestone bed has a thickness of 40 to 60 ft. The great width of ore, as much as 400 ft. in some of the stopes, is due to the folding, wherein the bed is repeated. In other cases the bed is stretched and pinched out. Dikes of Tertiary rhyolite cut across the country and, in places, sills overlie the

Jan 1, 1925

By AIME AIME

FOR the mineral industry, as for many others, the year 1944 brought to fruition the seeds planted in previous war years. Accomplishment in attaining ends in the production of minerals has given more time for the consideration of postwar problems, such as plans for resuming production for civilian uses and measures to prevent possible mass unemployment. The hectic atmosphere in production circles lessened during the latter half of 1943, conditions becoming static during 1944 as peak production rates were reached. Withdrawal of deferment of young men from the mining districts by Selective Service connotes that man power at the battlefronts became more important than the persistence of pressure for metal production. This is in contrast to the return of soldiers in 1943 to augment the labor ranks in the mining districts. The year ended in the midst of changing needs. Over-all metal production in the United States in 1944 will record a lessening, compared with the previous year owing to labor shortages which affected both development work and ore output.

Jan 1, 1945

By Carle R. Hayward

THOUGH recent months have seen a rapid decline in lead-smelting activity and consequent uncertainty as to the future, the first half of the year showed progress in keeping with similar activity in other metals. Demand for scrap increased and various lead-bearing materials found their way to plants producing secondary lead. Some of these materials introduced complications into normal smelting procedure and were the cause of many conferences among plant officials attempting to find the most satisfactory method of treatment. If a blast furnace is to do itself justice it must be run with an open charge. Troubles inevitably result when materials are added to a charge which tighten it up and pre- vent free burning of the coke and con- sequent rapid smelting with a clean hearth This fact has long been recognized by plants producing primary lead, but only recently only it received the attention it deserves.

Jan 1, 1938

By AIME AIME

IN ACCORDANCE with the provisions of the Rules of Procedure of the American Engineering Standards Committee, the American Society for Testing, Mate-. on Feb. 15, 1921, submitted for approval by the A. E. S. Committee certain Standard Specifications for Copper, all of which were adopted or in process prior to Jan. 1, 1920, and sent with the standards the following histories of development and statements of use. FOR SOFT OR ANNEALED COPPER WIRE (B3-15) These specifications were originaly adopted by. the American Society for Testing Materials in 1912. They were prepared by a committee of the Society designated as Committee B-1 on Copper Wire. The committee consisted of eleven members; representatives of five manufacturers of -copper wire, of four manufacturers of electrical apparatus, and of two firms of consulting and contracting engineers. The members of the committee were designated by the officials of the companies to act as their representatives in the committee.

Jan 1, 1921

By Clyde E. Williams

THROUGHOUT its history the American iron and steel industry has constantly striven to improve the quality and reduce the cost of its products. No one needs to be told how well it has succeeded. Its success in making steel products at such a low cost has been achieved mainly through large-scale production. While costs have gone down as the rate of production and the degree of mechanization increased, quality of product has been actually improved. Thus high-tonnage records are important only in the light of high quality of the steel. Quality is the watchword! Continual improvement in quality has come as a result of research, not only in the laboratory but in the large commercial units in the plant. In fact, so many operations of the industry are on such a huge scale that experimental work must be done under commercial operating conditions so every progressive steel plant is a research laboratory.

Jan 1, 1938

By W. O. Crosby

INTRODUCTION. THE crystalline belt of the Atlantic Seaboard, south of New York, attains its maximum breadth of 220 miles on the northern border of North Carolina; and in this State it is most widely characterized by the occurrence of gold in workable deposits. Half a dozen auriferous belts have been recognized by Nitze and Hanna.1 These are, in the main, coincident in position and trend with the NE.-SW. zones of metamorphic slates and schists, which, more than any other feature, give character to the geological map of North Carolina. The central gold-belts, accompanying the main zone of slates and associated igneous rocks, are much the more important and persistent, and may be regarded as continuous northward across Virginia and southward into South Carolina. Tile eastern belt, on the other band, is the shortest and, economically, one of the least important. Its extreme length does not exceed 25 miles, the narrow band of slaty rocks to which it belongs passing, both NE. and SW., beneath the coastal-plain formations. But, although limited in area and production, this belt is, perhaps, comparable with the central belts or any part of the sea-board crystallines in the variety of conditions under which the gold occurs. It lies chiefly in the NE. part of Franklin county and the NW. part of Nash county, on the watershed of Fishing creek and other tributaries of Tar river. The elevation is between 400 and 500 ft. ; and the Tertiary peneplain has here an exceptionally perfect development, the reliefs separating the slightly incised stream-courses consisting of broad, flat-topped peneplain remnants, bounded by gentle lateral slopes.

Mar 1, 1908

By C. H. Samans, G. F. Tisinai

HARDENING and embrittlement of the ferritic chromium stainless steels at temperatures near 885 °F have been known for a long time.' However, no satisfactory explanation has been given. Both ordering and precipitation hardening have been suggested. Fisher, Dulis, and Carroll2 discovered a chromium-rich body-centered-cubic precipitate in embrittled alloys. Subsequently, Williams' and Wright4 also have found evidence of this body-centered-cubic constituent. William's hardness, electrical resistance, and magnetic studies led to his proposal of a new constitutional diagram for the Fe-Cr alloys. The new feature of this diagram is the eutec-toidal decomposition, below about 970°F, of the s phase into two stable body-centered-cubic solid solutions, one rich in iron and the other rich in chromium. An observation of Heger5 that the amount of s phase has increased and the amount of chromium-rich body-centered-cubic phase decreased in the interval 5000 to 32,600 hr at 900°F, even though the alloy increased in hardness, casts some doubt on this diagram. If precipitation hardening causes the embrittlement, the precipitate probably is always coherent with the matrix, since no evidence of overaging has been reported. It cannot be stated positively, however, that Fisher's body-centered-cubic constituent is the embrittling phase. According to Preston's data,6 such a chromium-rich phase should have a parameter less than about 0.5 pct larger than that of the iron-rich matrix lattice. Moreover, the constitutional relationships whereby Fisher's constituent forms, and whether it is stable, metastable, or a transition phase, are not yet completely clear. The recent studies of Wright4 and of Lommel,7 as well as the earlier studies of Becket8 and of Hochmann,9 have shown that 885°F hardening occurs in relatively pure Fe-Cr alloys. No evidence of its occurrence or absence in chromium itself has been reported. The rate of hardening in high purity alloys seems appreciably slower than that in alloys containing larger amounts of impurities (chiefly carbon and nitrogen). This may be due merely to the absence of hardening and straining effects from precipitated carbides and/or nitrides. These observations on high purity alloys make it seem unlikely that 885 °F hardening is caused by a constituent containing other than iron and chromium atoms, e.g., carbides and/or nitrides. Wright,4 Lommel,7 and Lena and Hawkes10 emonstrated the accelerating effects of a finely dispersed precipitate of (probably) chromium nitride on the hardening reaction. This appears to be evidence that lattice straining increases the rate of nucleation of the hardening constituent. Some new observations on 885°F hardening are reported here. They show an effect of preheat treatment that should contribute to a better understanding of the 885°F hardening phenomenon. They also clarify a discrepancy which exists in the literature. Some investigators have reported most rapid hardening at 885", whereas others have reported it at 930°F. The present work also shows that 885°F hardening does not occur in electrolytic chromium, and that any long range ordering type of reaction affecting any sizeable part of the volume is unlikely. Materials Studied Table I shows the currlposition of the alloys used in this investigation. In these alloys carbon and nitrogen are present in roughly similar amounts. Presumably both elements precipitate, as carbides and/or nitrides, during the heat treatments given.

Jan 1, 1958

By R. Hastings Keller, Ralph E. Esarey

Oil and gas activities in Indiana during 1943 continued to decline at about the same rate as in 1942. New development, production, and prospecting, all showed the results of Federal regulation, low price for crude oil and shortages of labor and materials. Several local stripper-well operations were shut down, but no large-scale abandonment has occurred as yet. During the year, 277 holes were drilled for oil and/or gas, of which 99 were completed as oil wells, 19 as gas wells and 159 as dry holes. This record was a decline of 21 per cent over last year in the total number of completed tests, 20 per cent in the number of oil wells and 9.5 per cent in the number of gas wells. As in the previous year, most of the drilling (82 per cent) was in the southwestern part of the state, Gibson County ranking first, with 77 completions and 49 oil wells. Posey County was second, with 59 completions and 20 oil wells. The remaining 18 per cent of the drilling was in the old Trenton oil and gas area. The total footage drilled during the year was 482,799 ft., a decline of 18 per cent from the previous year. Of this, 146,559 ft. was wildcat footage. The total initial production of the oil wells completed was 6362 bbl. and of the gas wells was 2,562,000 cu. feet. Three tests in the old Trenton area were drilled into the Cambrian and reported nothing more than tar residue. A Devonian test was to be made in the Griffin field in the Wabash River but owing to the delay caused by Federal restrictions this test did not get started in 1943. It is expected to spud in March 1944. The new discoveries in 1943 were virtually all in the southwestern part of the state, and all, so far, one-well pools, except the North Owensville pool, in Gibson County. The latter was brought in during the month of February and by the end of the year nine wells were producing in the pool, with a reported initial yield of 1260 bbl. per day. By the end of the year it had a daily average production of 401 bbl. and an accumulated production of 39,129 bbl. The average gravity of the oil is reported to be 35.6. On the Ohio-Indiana state line, early in 1943, a new pool was opened up in the old Trenton area. The discovery well was on the Ohio side of the line. An offset well was completed on the Indiana side, with an initial yield of 64 bbl., and settled down to 5 bbl. per day. This well produced 1154 bbl. up to Dec. 31, 1943. There was no further development here, because of the Federal Conservation Order M-68, restricting drilling to one well on 40 acres. The development pattern usually followed in this area is one well to 5 acres. The E. Rogers field was extended by one pool (Table 4). Most of the development in the oil-field pools during the year took place in the Kirksville pool, in Gibson County, and the Caborn pool, in Posey County. The crude-oil production in 1943 was approximately 5,273,000 bbl., a decline of 29 per cent from the previous year. The Griffin field, of Gibson and Posey Counties,

Jan 1, 1944

By R. Hastings Keller, Ralph E. Esarey

Oil and gas activities in Indiana during 1943 continued to decline at about the same rate as in 1942. New development, production, and prospecting, all showed the results of Federal regulation, low price for crude oil and shortages of labor and materials. Several local stripper-well operations were shut down, but no large-scale abandonment has occurred as yet. During the year, 277 holes were drilled for oil and/or gas, of which 99 were completed as oil wells, 19 as gas wells and 159 as dry holes. This record was a decline of 21 per cent over last year in the total number of completed tests, 20 per cent in the number of oil wells and 9.5 per cent in the number of gas wells. As in the previous year, most of the drilling (82 per cent) was in the southwestern part of the state, Gibson County ranking first, with 77 completions and 49 oil wells. Posey County was second, with 59 completions and 20 oil wells. The remaining 18 per cent of the drilling was in the old Trenton oil and gas area. The total footage drilled during the year was 482,799 ft., a decline of 18 per cent from the previous year. Of this, 146,559 ft. was wildcat footage. The total initial production of the oil wells completed was 6362 bbl. and of the gas wells was 2,562,000 cu. feet. Three tests in the old Trenton area were drilled into the Cambrian and reported nothing more than tar residue. A Devonian test was to be made in the Griffin field in the Wabash River but owing to the delay caused by Federal restrictions this test did not get started in 1943. It is expected to spud in March 1944. The new discoveries in 1943 were virtually all in the southwestern part of the state, and all, so far, one-well pools, except the North Owensville pool, in Gibson County. The latter was brought in during the month of February and by the end of the year nine wells were producing in the pool, with a reported initial yield of 1260 bbl. per day. By the end of the year it had a daily average production of 401 bbl. and an accumulated production of 39,129 bbl. The average gravity of the oil is reported to be 35.6. On the Ohio-Indiana state line, early in 1943, a new pool was opened up in the old Trenton area. The discovery well was on the Ohio side of the line. An offset well was completed on the Indiana side, with an initial yield of 64 bbl., and settled down to 5 bbl. per day. This well produced 1154 bbl. up to Dec. 31, 1943. There was no further development here, because of the Federal Conservation Order M-68, restricting drilling to one well on 40 acres. The development pattern usually followed in this area is one well to 5 acres. The E. Rogers field was extended by one pool (Table 4). Most of the development in the oil-field pools during the year took place in the Kirksville pool, in Gibson County, and the Caborn pool, in Posey County. The crude-oil production in 1943 was approximately 5,273,000 bbl., a decline of 29 per cent from the previous year. The Griffin field, of Gibson and Posey Counties,

Jan 1, 1944

By Clyde E. Williams

THIS review of the progress made in iron and steel metallurgy during the past year is confined to developments in this country. It attempts to give examples to illustrate progress made rather than to appraise results. As a result of the gradually diminishing supply of rich iron ores and of predictions made as to the probable life of the iron-ore reserves of the Lake Superior District, attention of iron and steel executives was directed to the question of beneficiation of iron ores. Laboratory and plant-scale experimental work was conducted on the wash ores .of Minnesota and an investigation, was, begun on the Old Range low-grade ores.

Jan 1, 1931

By Eugene McAuliffe

THE heavy shrinkage in the production of bituminous coal has reflected adversely in the matter of tonnage produced by stripping arid mechanical loading machinery. The purchase of stripping and underground loading equipment has likewise been circumscribed. How- .ever a growing percentage of bituminous coal is being loaded by stripping and mechanical loading machinery. This situation is due to the fact that numerous strip pits were able to operate in Illinois and Indiana when under- cover mines were subjected to labor interference, a further advantage gained by their ability to produce and market coal at a price below that of the undercover mines. The mines equipped with mechanical loading. apparatus have enjoyed more continued operation for the double reason that the companies using coal-loading machinery are, generally speaking, more substantial and in better financial condition than many of the smaller properties who maintain hand-loading methods, and the market advantage due to lower production costs also reflects to the advantage of the undercover mines using mechanical loading equipment. Where a number of mines are con- trolled by one company, those not equipped with loading machinery and suffering from higher producing costs have often been closed, with the available tonnage concentrated in the more modernly equipped mines.

Jan 1, 1933

By JOHN R. SUMAN

COMMENCEMENT exercises this year have a peculiar significance because the graduating students are entering upon their life's work at the most critical time in the history of the United States. We are engaged in a great struggle the outcome of which is none too clear even to the best informed students of international affairs. We are starting late in a vicious world conflict where it is generally recognized that our adversaries have distinct superiority over us in armament on the land, on the sea, and in the air. We have the gigantic task of building up our armed forces and armament and at the same time supplying our allies with equipment which they must have. We can do this job if we are given sufficient time, but there is a possibility that the war will be over before we are ready. Few realize the seriousness of this situation. If this fight is to be won-and we dare not try to visualize the future of this country if it is lost-all dissension and bickering between Congress, capital, labor, and agriculture must cease. When and where voluntary co-operation proves inadequate for the successful conduct of the war effort, laws must be enacted or strengthened to achieve our purpose.

Jan 1, 1942

By Mitchell, Edmund I.

VARIOUS suggestions as to proper fees for engineering services have been put forth by individual practitioners and by the American Institute of Consulting Engineers, the Connecticut Society of Civil Engineers, the Iowa Engineering Society and the Mahoning Valley (Ohio) Engineers, for the guidance of both the engineer and his client. The American Institute of Architects also has a schedule of minimum charges (revised 1908). So far as can be determined, however, the four national societies representing civil, mining, mechanical and electrical engineering have never given consideration to this question. An examination of technical periodicals published during the past decade shows that these schedules make provision for three methods of charging; i.e., (A) a percentage of the cost of the completed project; (B) a per diem rate; and (C) a fixed sum. Suggested minimum charges are as follows:

Jan 1, 1921

By J. C. Swartz

Measurements of the effect of precipitation stresses on the solubility of cementite (Fe3C) precipitates in a iron are reported. Solubilities were determined from measurements of the Snoek relaxation due to interstitial carbon after quenching from various equilibrium treatments. Stress-free precipitates were obtained by a spheroidizing treatment of vacuum-melted Fe 0.06 wt pet C. Subsequent equilibration treatments were designed to suppress nucleation of other precipitates. The results for stress-free cementite give a heat of solution of 14.8 i 0.2 keal per mole and an entropy change of 1.1 i 0.2 eu in the temperature range 400" to 715°C. Comparison with previous data indicates that the heat of solution increases about 6 keal per mole as temperature increases from 700" to 1000°C. Data on self-stressed cementite in quench-aged specimens of Fe 0.013 wt pet C indicate 1) an apparent heat of solution of 12.1 i 0.4 keal per mole in the range 280" to 690°C, 2) a strain energy of- 1.1 keal per mole Fe3C accompanying precipitation at 280°C, and 3') a gradual decrease in the strain energy of precipitation with increasing equilibration temperature. In com-parison with 2 and 3 the strain energy calculated for an isotropic model is 1.7 keal per mole Fe3C. The lower values obtained from the experiment indicated substantial stress velaxation by dislocation motion. WHEN a supersaturated solution of carbon in a iron is aged at temperatures in the range 200o to 700oC, the carbon clusters by interstitial diffusion and forms cementite (Fe3C) precipitate particles. Unstressed cementite has a volume per iron atom 9 pet higher than that of a iron;' hence, cementite precipitate particles are usually under pressure from the iron matrix. The pressure would tend to increase the solubility of cementite in iron.' This report describes anelastic measurements of the solubilities of self-stressed and stress-free cementite in a iron. Previous determinations of the cementite solubility are summarized in Table I. The method of cementite formation for each reference was studied to ascertain the state of stress of the cementite. The results judged to be for stress-free and stressed cementite are distinguished in the table. In the next section an estimate of the stress effect is obtained which is clearly too small to account for the large difference between the previous results in parts A and B of the table. THEORETICAL Let AGO be the standard free-energy change of the reaction Fe3C (eem.) = 3Fe (a) + C (in a) [1] in the absence of stresses. Since cementite precipitates appear to be rather pure10 and the carbon is so dilute in the iron,8 the cementite and iron of Eq. [ I] for the stress-free case have essentially unit activities and the activity of carbon equals its atom fraction xoC Then the stress-free equilibrium is expressed by RT In XoC = -?GO 121 To first approximation the change in the chemical potential of carbon due to the precipitation stresses equals the elastic strain energy W accompanying precipitation of a mole of cementite.2 Hence, in the presence of the precipitation stresses the equilibrium is described by RT In x sq = -?G° + W [3] where xsC is the mole fraction of dissolved carbon in the stressed case. An approximate value of W can be obtained from analysis of the inclusion problem in elasticity theory. The inclusion is a small portion of the matrix phase which has suffered a transformation while still imbedded in the matrix. In the absence of the constraint of the matrix the transformation would be equivalent to a uniform dilational strain eT. Both the matrix (a) phase and inclusion (0) phase are assumed to be homogeneous, isotropic materials. When the a and 0 phases have the same elastic moduli, which is approximately true for iron and cementite,11 the total strain energy per mole ß is12 2µVß(eT)2(3 +4 µx)-I [4]

Jan 1, 1968