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By F. W. Hillnhutter

In plant tests with a 9.7 m hearth diameter high top pressure blast furnace the influence of disintegration of sinter during low-temperature reduction on blast furnace performance was evaluated. The blast furnace burden during the test period consisted of 74% self-fluxing sinter with a basicity of CaO/Si02 = 1.3, 15% pellets, 6% lump ore, and 5% recirculated slags. The sinter for the test was produced in a modern sinter plant. By changing the fuel rate and/or the MgO content at a constant basicity CaO/Si02 sinters with different low-temperature disintegration properties could be produced. The blast furnace was equipped with pressure monitoring devices at medium height of the furnace stack wall. This device provided in addition to the normal operating data readings of pressure losses in the upper and lower part of the furnace. The basic physico-chemical factors determining low-temperature disintegration are explained. The testing devices and the extent of quality control measures of sinter during the test period are outlined. Conclusions are drawn from the plant test in relation to sinter properties.

Jan 1, 1977

Two Canadian mining companies, Noranda Mines, Ltd., and Wright-Hargreaves Mines, Ltd., have agreed to buy $500,000 worth of shares each in Anglo-American Exploration Ltd., controllers of thousands of acres of possible oil-rich land in southern Saskatchewan and Manitoba. Samuel Clarence Nickle, Sr., reported as possible president of the newly formed exploration company, said that $20 million in assets have been accumulated by the firm, mainly in the Williston basin in parts of the Dakotas and Montana, aid extending into Southern Manitoba and most of Saskatchewan. The M. A. Hanna Co. reported a record profit for the seventh consecutive year with total 1951 profit reaching $14,081. The company handled a record 16.8 million tons of iron ore in 1951, compared with 14.9 million tons in 1950. The company is also preparing to open four iron ore mines in the Lake Superior district which are expected to produce more than 5 million tons annually by 1954. The company built two new iron ore concentrating plants at Mesabi range mines in 1951,a with a third plant going into, operations soon.

Jan 1, 1952

By L. D. Jaffe, D. C. Buffum

EARLY papers1-' reported that temper brittleness is influenced by microstructure. This conclusion was based on room temperature impact tests, the inadequacy of which has been pointed out. Pellini and Queneau7 measured impact energy absorption at —80O to +25oC for several microstructures. On the basis of the shift, associated with temper brittleness, in the energy vs testing temperature curve they concluded that tempered martensite is somewhat more susceptible to temper brittleness than is tempered pearlite. The range of temperatures was insufficient to give complete curves covering the transition from tough to brittle behavior, so it is difficult to evaluate quantitatively the shift for the different microstructures. Also, the smaller shift of pearlite might be attributed to its already being temper embrittled at its temperature of formation. Accordingly, blanks 2 3/16 in. long were cut from a heat of SAE 3140 hot rolled steel barstock, 5/8 in. diameter, on which other work has been reported? A set of blanks was austenitized 1 hr at 900°c, water-quenched, tempered 16 hr at 675oC, and water-quenched, giving a microstructure of 100 pct

Jan 1, 1954

Inflation, tight money and keen competition spur companies to consider advanced material handling systems capable of reducing cost per ton of moving ore, waste or men and supplies. Since transportation charges account for an average of about 25% of the total delivered price of a product, then this cost center may actually determine the economic value of a new deposit. This being so, it is interesting to note that of the 1.4 billion tons of revenue freight carried by all Class I carriers of the nation in 1967, over 247 million tons or 17.5% were industrial minerals or products dependent on industrial minerals, i.e., glass, gypsum board, brick, etc. Because most bulk commodities have a comparatively low market value and are usually classified for lower than normal freight rates, railroads rely on large volumes and better equipment utilization to effect an equitable return. It is for this reason that the unit and shuttle train concept came into being. The average rate per ton-mile of all materials hauled by rail in 1968 was 1.31 cents. The low rates existing for industrial minerals contributed to this low average as did unit and shuttle train rates.

Jan 10, 1969

By D’Arcy A. Shock

In this year's review, the concept of solution mining has been expanded to include total solution as well as the technology of leaching, or partial solution methods. Leaching methods continue to make strides in the processing of metallic minerals, particularly in copper and uranium production. No quantitative data are available on the increase of leach operations; however, it is known that there were more systems installed in 1969 and that the estimated 15% of U.S. domestic production of copper produced in 1968 was by leach methods.1 While the number of publications appearing during the year were few,2,3 there were special sessions in this field at the AIME Annual Meeting and SME Fall Meeting in 1969 and more scheduled for these meetings in 1970. Significant areas that should be mentioned are: the continuing interest in bacteria to convert sulfide sulfur to acid thus reducing reagent costs in both copper and uranium sulfide ores, the exploration of leaching agents other than common mineral acids or alkaline solutions,4,5 kinetic studies of leach mechanisms and the development of microfractures for increased leach solution penetration by use of chemical or atomic explosives.6,7

Jan 1, 1970

I. N. KNAPP, Ardmore, Pa. (written discussion*).-Captain Lucas has made an important contribution to our, knowledge of Belle Isle, especially as to the outline of the sulphur deposit, and the pronounced irregularity of the salt surface. I agree with his view, that the elevation or mound that constitutes Belle Isle may consist of several salt domes formed at different periods. It may be interesting to note the high gas pressure encountered in pockets in the salt by my No. 1 Belle-Isle well. While drilling a dry hole with cable tools, we sometimes struck. pockets of gas which would float the tools, so that drilling had to be suspended sometimes for several hours at a time, until the head of gas was exhausted, and this with a string of tools, 5-in. (127 mm.) stem 36 ft. (10.9 m.) long, that weighed complete about 3500 lb. (1587 kg.). At about 1800 ft. (548 m.), we struck the largest gas pocket and the string of tools was thrown up and nearly out of the hole. When it dropped back it made several loops

Jan 1, 1918

CHARLES E. GUILLAUME,* .Sèvres, France written discussion?).-Referring top. 2052, experiments made at the end of the year 1884showed a remarkable agreement between the indications of various verre dur thermometers of which all the corrections had been determined with the greatest possible precision. The maximum deviations not attributable to the comparisons themselves were then about 0.002 to 0.003 degree. Much later, greater differences began to show. They were caused by the fact that the glassmaker-had modified the composition by adding to it a small quantity of lead. Efforts are now being made in France to obtain a regular, supply of glass made according to the old formula. The determination of the boiling point of sulfur made by Chappuis,1 444.5°, accords very well with the value noted on p. 2054. The International Committee of Weights and Measures and the General Conference have already considered the future abandonment of the hydrogen scale in favor of the thermodynamic scale. The hydro-gen scale appears to be, in their estimation, a transitory one, happily so closely approaching the final scale that no correction should be necessary for all measurements of temperature made during the last 30 years.

Jan 12, 1919

The new, internationally-owned Savage River Mines iron ore mining, concentrating and pelletizing project, built and operated by Pickands Mather & Co. International, was dedicated March 6 at Port Latta, Tasmania, Australia. Construction of the $79 million project began in 1965 and involved an open pit mine and concentrating plant plus a complete town for about 350 employees at Savage River; a 53-mile pipeline to transport the concentrates; a pelletizing plant and shipping facilities at Port Latta, which is on Bass Strait separating Tasmania from the Australian mainland. The project has a rated capacity of 2.25 million Ltpy of high-grade magnetite pellets, which will be sold to five Japanese steel companies under 20-year contracts. The open pit mine is located in the central portion of the Savage River deposits. Mining equipment, capable of moving 10 million tpy of ore and overburden, consists of four 6-cu yd electric shovels and 12 50-ton trucks. The concentrating plant, with a design capacity of 5 million tpy of ore, will use magnetic separators to upgrade the ore, which averages 38% iron, to a concentrate averaging 67% iron.

Jan 4, 1968

By William Y. Warren

Messrs. Thomas & Cross, having leased from the Akron Cement Company from twelve to fifteen acres of abandoned cement-tunnels and chambers, for the purpose of propagating mushrooms for the market, commenced operations about a year ago, and are now beginning to furnish mushrooms in quantities to the local markets of Buffalo and Rochester. The quarries, or, more properly, the mines, of the Cement Company are located at Akron, Erie County, PIT. Y. The cement-rock occurs in a stratum about 71/2 to 8 feet in thickness, which is overlain by from 1.5 to 25 feet of limestone and flint-rock. There is a gentle rise from the opening of the tunnel inwards, giving a natural drainage and leaving the chambers comparatively dry. The roof is good and is supported by pillars and heavy timbers. The mushroom-beds are located about 300 feet from the opening of the tunnel, and are made in the form of mounds about 3 feet by 12 feet, at the base, and 24 feet high, giving to the chambers the appearance of a subterranean graveyard. Many experiments have been made to determine the best form for the beds, and the mound

Jan 1, 1889

By Howard E. Parkinson, John N. Murphy

The past five years have seen communications techniques and hardware developed by the Bureau of Mines and its contractors increasingly brought into use in U.S. mines. The Bureau philosophy has been to help develop and introduce new hardware that goes as far as possible toward meeting the mining industry's needs. The Bureau programs are also designed to provide continuous fallout of new communications capabilities which are introduced to the mine operators as they occur. As more progress is made in meeting mine communications needs, it is hoped that the mining industry will readily adopt the equipment and techniques that it finds most useful in meeting its individual needs. This paper reports on recent advances achieved in the development of improved mine communications systems. In May 1975 the U.S. Bureau of Mines (USBM) conducted a mine communications technology meeting to provide a brief overview of the USBM communications technology developments in the past 5 yr. This meeting lasted for 1 1/2 days. Therefore, I have elected to narrow this paper to a brief review of recent underground mine communication developments. The following will be discussed: 1) Ultra-high frequency (UHF) radio for fan hole drill operators;

Jan 1, 1978

Dr. Oldshue has provided a useful summary of a voluminous subject and my task will be to select and direct attention to those areas of mixing theory and practice which are germane to mineral processing in general, and to fine particle treatment in particular. Pulp mixing in impeller actuated reactors occurs in mineral processing in several different applications: (1) emulsification of reagents; (2) mixing pulp with 'reagents as in conditioning for subsequent operations (such as flotation, flocculation or agglomeration) ; (3) high intensity agitation, as in (a) disintegrating and dispersing aggregates, and (b) aggregating particles as in shear flocculation or in selective agglomeration; (4) hydrometallurgy; (5) hydrometallurgy with gas phase (e.g., Arbiter process); . (6) flotation in sub-aeration machines. Attention is invited to 3 above in which two opposite effects can be induced by proper choice of chemical treatment and hydrodynamic conditions. Successful processes for treating mineral fines require excellent aggregate dispersion in order to fully accomplish the liberation stage. Some processes depend further upon selective aggregation following dispersion. The term “dispersion” is often used in different senses which for present purposes will be clarified at the bottom of the next page.

Jan 1, 1979

By T. M. Allen, W. H. White

THE Greenwood-Grand Forks area of southern central British Columbia, known as the Boundary District, has a long history of mining exploration and production. At the turn of the century this was the premier copper mining camp in the British Empire, its total production amounting to some 20 mil- lion tons. Most of this ore came from the great Granby mines at Phoenix, but the Motherlode mine at Deadwood camp, 6 miles to the west, and several mines in Summit camp, 5 miles north of Phoenix, made important contributions. The large deposits were exhausted in 1918 and the district since has seen only desultory exploration and salvage operations. The orebodies are mineralized skarn zones in limestone members of a thick series of Upper Paleozoic sedimentary and volcanic strata. Chalcopyrite is the primary ore-mineral. Copper carbonates and silicates occur sparingly in outcrops, but the oxidized zone generally is very shallow. Much of the surface is mantled by glacial drift which in most places ranges in thickness from 2 to 15 ft. In some of the hanging valleys, however, the glacial drift may be as much as 100 ft thick and may assume drumlin-like forms.

Jan 1, 1954

By H. C. Fiedler

THE development of the cube-on-edge secondary re-crystallization texture in Si-Fe strip depends upon the ability of inclusions to restrain normal grain growth. This ability is determined by the number and size of inclusions, which, for a given composition, is controlled by the thermal history of the material during the prior processing.' It has been shown2 that increasing the silicon content decreases the solubility of sulfur, and it is the purpose of this note to show the consequences of this decreased solubility for secondary recrystallization. Heats were made as previously described and cast into graphite molds.' The compositions are shown in Table I. Slabs 1 in. thick were cut from the ingots and either hot-rolled from 1000°C in the as-cast condition or after one of the heat treatments described later. The processing to the final gage of 12 mils followed the previous procedure.' To avoid cracking, the 5.2 pct Si alloy was cold-rolled at 150" to 200°C rather than at room temperature. The percent cube-on-edge texture developed by isothermal heat treatments was determined by dividing the maximum torque measured on disk sam-

Jan 1, 1968

By J. V. Gluck, Ping-Wang Chiang

The tellurium-rich region of the Sb-TI-Te ternary system was investigated by means of DTA, metallo-graphic, X-ray, and electron beam microprobe techniques on the sections Sb2Te3-T12Te3, SbTlTe2-Te, SbT1Te2-Sb2Te3, and SbTlTe2-T12Te3. The phase behavior of this region is summarized in terms of four ternary invariant reactions and a schematic reaction diagram is suggested. Isopleths for the sections SbT1Te2-Sb2Te3, Sb2Te,-T12Te3, and SbTlTe2-Te were constructed, and a schematic diagram of the projections of the liquidus lines and invariant planes is presented. No evidence was found to support the existence of the ternary compound "SbTlTe3", or pseudo-binary behavior of the section T12Te3-Sb2Te3, as reported by Borisova and Efremova. Electrical conductivity, Seebeck coefficient, and thermal conductivity measurements were made at room temperature on fully annealed samples. 1 HE phase relationships in chalcogenides are often complex and difficult to resolve, particularly since the approach to equilibrium is a rather slow process. For example, the phase diagram of the T1-Te binary system was in doubt until clarified by Rabenau et al.,1 the phase fields at compositions near Bi2Te3 in the Bi-Te binary system have only recently been satisfactorily elucidated by Glatz,2 and there may still be some question as to the extent of the Sb2Te3 field in the Sb-Te system.3-5 In ternary systems, the existence of the compound "AgFeTe2" was the subject of a number of conflicting reports6-8 and the stoichiometry of the composition "AgSbTe2" was in doubt for a period of time.9 Recently, questions have arisen regarding the existence of certain compounds in the ternary systems Bi-Tl-Te10-14 and Sb-Tl-Te.15 The impetus for studies of these latter systems stemmed from the report of Borisova et a1.10 of a congruently melting ternary compound, "BiTlTe3", which apparently had extremely favorable thermoelectric properties for room-temperature cooling applications. Attempts by other investigators to produce the compound or confirm the transport properties proved to be unsuccessful.12-14 Recently, Chiang and Gluck14 reported studies of the phase relations in the tellurium-rich region of the Bi-T1-Te system which indicated that the section T12Te3-Bi2Te3 was not pseudobinary as suggested by Borisova et a1.10 The contention of Spitzer and sykes12 was supported that the composition "BiT1Te3" was multiphase, with the primary constituent actually being BiTlTe2, a compound whose existence has been well demonstrated.16,17 The investigation reported in the present paper was prompted by a later report of Borisova and Efremova15 on a similar study of the section T12Te3-Sb2Te3 from the Sb-T1-Te system. They also claimed this section to be pseudobinary, and that a ternary compound "SbTlTe," was formed peritectically. Some "preliminary" crystallographic data were given for the compound and thermoelectric transport properties were presented. In view of the questions concerning the behavior of the Bi-T1-Te system and the existence of the compound "BiT1Te3" it was suspected that the Sb-T1-Te system might behave in a similar fashion, particularly in light of the known existence of a compound SbT1Te2, iso-structural with BiT1Te2.17 Consequently, an investigation was undertaken to clarify the phase relationships in the tellurium-rich region of the Sb-T1-Te system. It is the purpose of this paper to present the results of this study, including a representation of the phase relations, isopleths for various composition sections, and the determination of some phase compositions and transport properties. EXPERIMENTAL PROCEDURES Commercially available high-purity (99.999+ pct) elements, purchased from the American Smelting and Refining Co., were used for the sample preparation. All samples were made from thoroughly mixed powders of previously prepared master alloys: SbTlTe2, Te, Sb2Te3, and T12Te3. Stoichiometric quantities of the constituents for each 10-g sample were weighed into a specially cleaned fused silica tube and sealed under a vacuum of better than 5 x 10-5 torr. The sealed constituents were fused and reacted at 650° to 750°C for at least 4 hr under continuous agitation in a "rocking" furnace, and the resulting product was air-cooled. The tube was opened and the sample was ground to a powder. A portion of the powder was rebottled in a DTA tube under vacuum, and the rest of the material was similarly resealed in a separate tube, re-fused in the rocking furnace, and again cooled to make the ingots for electrical and microstructural studies. All samples were subjected to further heat treatments as discussed in the section on experimental results. Each DTA tube was made of 7-mm-OD fused silica tubing with a concentric 2-mm-ID depression about 4 mm long formed in the bottom to accommodate a thermocouple. The size of a DTA sample was 0.5 to 1.0 g. An Aminco Thermoanalyzer whose accuracy was within 2°C18 was used for the DTA measurements. The metallographic samples were prepared by conventional techniques. A solution of FeCL dissolved in a methanol-HC1 mixture was found to be the most satisfactory etchant. Electron beam microprobe scanning and point-count examinations were made on polished and unetched samples using an ARL Electron Microprobe at an electron beam voltage of 20 kv. The detectors were set to receive characteristic La1 radiation. Calibration standards of the pure elements were incorporated in each sample mount; quantitative point counts were calibrated by a method similar to Ziebold

Jan 1, 1969

By R. C. Gould, A. M. Skov, L. F. Elkins

Comparison of long term decline in oil production during cyclic waterflooding or pressure pulsing of part of the Driver Unit with steady injection-imbibition flooding in the Tex Harvey area led to large expansion of flood in the Driver Unit on the steady injection basis. While the flood has been successful, the major problem has been attainment of satisfactory oil production rates in most of the wells. Large volume fracture treatments of low capacity wells were unsuccessful in achieving sustained increases in production. A two-section area in the Driver Unit has already recovered 620 bbl of oil per acre by waterflood but other areas have not performed so well. Sun Andres water containing 300 to 500 ppm H,S is sweetened to 0.5 to 1 ppm H,S by extraction with oxygen-free flue gas. This prevents contamination of gas produced in the area and apparently it has reduced corrosion in minimum investment, thin-wall, cement-lined water dktribution systems. Cement-lined tubing in injection wells has mitigated corrosion as effectively as thick polyvinyl chloride films have, and at less cost. Introduction As reported in the literature the Spraberry field of West Texas has presented unusual problems for both primary production and waterflood ing. Earlier information from the Spraberry Driver Unit included conception and evaluation of cyclic waterflooding or pressure pulsing in a nine-section pilot test as an aid to extraction of oil from the tight matrix rock and as a boost to normal capillary imbibition forces An additional 5 years' operation in that area, and performance of expanded steady injection water-flood, now covering a total of 68 sq miles, are reported herein. In addition, since the Driver Unit is one of the largest waterfloods in areal extent in the U. S., many operating experiences are presented for the benefit of engineers concerned with operation of other Spraberry floods or with other waterfloods where this reservoir technology and/or water handling technology may be adaptable in part. These include: (1) attempts to improve producing well capacity through large volume fracture treatments, (2) long-term performance of water treating plants utilizing oxygen-free flue gas to extract H,S from sour San Andres water, (3) performance of thin-wall cement-lined pipe in water distribution systems including comparison between those sections carrying raw San Andres water and those carrying treated water, and (4) comparison of performance of various lining materials and subsurface equipment in water supply and water injection wells. These experiences are reported without regard to whether results are good, bad or indifferent. Since the operations reported are limited to the techniques, materials, and equipment actually used in the Driver Unit, no comparison is possible with results of other approaches used in other Spraberry floods or in waterfloods generally under different conditions. However, an attempt is made to quantify these experiences as much as possible in the space available to permit other engineers to select those parts applicable to eheir problems. Background The Spraberry, discovered in Feb., 1949, is a 1,000-ft section of sandstones, shales and limestones with two main oil productive members—a 10- to 15-ft sand near the top and a 10- to 15-ft sand near the base, having permeabilities of 1 md or less and porosities of 8 to 15 percent. Extensive interconnected vertical fractures permitted recovery of oil on 160-acre spacing from this fractional-millidarcy sandstone, but they made capillary end effects dominant. Primary recovery by solution gas drive is less than 10 percent of oil in place, with most wells declining to oil production of a few barrels per day when reservoir pressures are still in the range of 400 to 1,000 psi. Partial closing of the fractures with declining reservoir pressure is believed to be the cause of such low production rates at these relatively high reservoir pressures. In 1952 Brownscombe and Dyes proposed that displacement of oil by capillary imbibition of water from the fractures into the matrix rock might significantly increase oil recovery from the Spraberry, overcoming otherwise serious channelling of water through the fractures." A pilot test conducted by the Atlantic Refining Co. during 1952 through 1955 indicated technical feasibility of the process; but low oil production rates averaging I5 to 20 bbl/well/D failed to create significant interest in large-scale waterflooding at that time." Humble Oil & Refining Co. conducted a highly successful 80-acre pilot test during 1955 through 1958 with

Jan 1, 1969

By M. Schwartz, S. K. Nash, R. Zeman

Knoop hardness in the rolling plane and in the longitudinal plane of hot-rolled and cold-rolled sheets of sublimed magnesiu?w was measured as a function of the angle between the long axis of the indenter and the rolling direction. These measurements were correlated with similar data taken on the (0001) and (1010) planes of a single crystal of magnesium where the hardness was measured as a function of the angle between the long axis of the indenter and the [1120] direction. The results were analyzed for compliance with the hypothesis of Daniels and Dunm to account for slip, and with a similar hypothesis to account for twinning. Some hardness anisotropy data are also presented for magnesium-indium and magnesium-lithium solid solution alloys. It is well known that the hardness of a crystalline specimen is different for its different surfaces, and also that the hardness is a function of direction within a single surface. Variations in hardness for single crystals have been found to be much larger than those for polycrystalline materials. Also, materials having low crystal symmetry were found to have a greater anisotropy of hardness than those of high symmetry. 0'Neill1 and Pfeil,2 using a 1-mm Brine11 ball, studied single crystals of aluminum and iron, respectively; and they found a variation of hardness of about 10 pct between readings taken along the principal crystallographic faces. Daniels and Dunn3 found that the Knoop hardness number varied about 25 pct as the long axis of the indenter rotated on the basal plane of a zinc single crystal. The variation on the (1450) plane was about 100 pct, and the average hardness on this plane was about twice that of the basal plane. They also studied the variation of hardness within the (loo), (110), and (111) faces of a single crystal of silicon ferrite and found variations of about 25 pct although the average values for these planes were almost identical. Single crystals of zinc were also studied by Meincke.4 He found that the Vickers hardness numbers varied about 30 pct depending on whether the axis of the indenter was parallel or perpendicular to the (1010) and (1110) planes. Mott and Ford,5 using a Knoop indenter, found a 25 pct variation in hardness on the basal plane of zinc. Crow and Hinsley6 studied heavily cold-rolled bronze, steel, brass, copper, and other metals. They found that the difference in hardness numbers based on the difference in the length of the diagonals of the Vickers indenter was from 5 to 12 pct. Some minerals and synthetic stones show a very large anisotropy of hardness. Robertson and Van Meter7 found the Vickers hardness of arsenopyrite to vary from 633 to 1148 kg per mm2. stern8 using the double-cone method on synthetic corundum found the hardness number to vary from 950 to 2070. And winchell9 reported a variation of hardness number from 184 to 1205 in kyanite. The variation of hardness as a function of direction in a given crystallographic plane in single crystals possesses a periodicity which is related to the symmetry of the lattice. Daniels and Dunn3 found a six-fold periodicity of hardness in the (0001) plane of zinc. They found that the hardness curves of silicon ferrite had a four-fold symmetry in the (100) plane, a two-fold symmetry in the (110) plane, and a six-fold symmetry in the (111) plane. Mott and Ford5 also reported a six-fold symmetry of hardness in the basal plane of zinc. And vacher10 found two-, four-, and six-fold periodicities of hardness in copper on the (110), (100), and (111) planes, respectively. The purpose of this paper is to report the results of an investigation on the anisotropy of hardness as a function of orientation in single crystals of mannes-ium, and samples of rolled magnesium, magnesium-indium, and magnesium-lithium solid solution alloys. The anisotropy of hardness of pure magnesium which had been hot rolled, and then cold rolled various amounts to fracture, was studied by means of Knoop indentation hardness numbers; and the results were correlated with the preferred orientation as determined by quantitative X-ray pole-figure data. A comparison was made of the hardness data obtained from the rolled sheets and those of single crystals of magnesium. In order to obtain a more fundamental understanding of the variation of hardness and of Knoop hardness testing, the data were analyzed by

Jan 1, 1962

By D. V. Edmonds, C. J. Beevers

Tensile tests were carried out on a! titanium containing 850, 1250, and 2700 ppm 0, and up to -500 ppm H. The tests were performed at -196", -78", 20°, 150°, and 300°C at a strain rate of -1.0 x 10??3 sec-1. Increasing oxygen content, increasing grain size, and decreasing test temperature resulted in enhanced embrittlement of the a titanium by the hydrogen additions. Metallographic observations showed that this can be correlated with the influence of these parameters on the introduction of cracks into the a! titanium by fracture of titanium hydride precipitates. CRAIGHEAD et al.1 reported that the hydrogen content normally found in commercial-purity a! titanium (60 to 100 ppm) was sufficient to cause a substantial lowering of the impact strength, and they attributed this embrittling effect of hydrogen to the precipitation of titanium hydride. Lenning et al.&apos; found that in commercial-purity a titanium there is an almost complete loss of impact strength at about 200 pprn H, which is approximately half the value needed to eliminate the impact strength of high-purity a titanium. They also showed that the presence of 3000 ppm hydrogen reduces the room-temperature tensile ductility of commercial-purity material to a value of the order of 10 pct; the corresponding hydrogen concentration for high-purity titanium is over 9000 ppm. It thus appears that the detrimental effect of hydrogen on the mechanical properties of commercial-purity titanium becomes evident at much lower hydrogen contents than for high-purity titanium. The main difference between the two types of a titanium might be expected to be the higher level of interstitial impurity in the commercial-purity grade. Jaffee et a1.3 studied the influence of temperature and strain rate on the hydrogen embrittlement of high-purity and commercial-purity ! titanium. In general, the behavior was the same for both materials; embrittlement was enhanced by decreasing temperature and increasing strain rate. Recent results from tests on commercial-purity a titanium containing 850 ppm O and varying amounts of hydrogen up to -500 ppm showed that the degree of embrittlement by hydrogen is intimately related to the fracture characteristics of titanium hydride precipitates.4 The present paper considers the interrelationship between the mechanical properties and micro-structural features of commercial-purity a! titanium containing 850, 1250, and 2700 ppm 0 and varying amounts of hydrogen up to -500 ppm. 1. EXPERIMENTAL PROCEDURE Three types of commercial-purity titanium supplied by IMI* were used in the investigation, and for the *Address: Witton, Birmingham 6, United Kingdom. purpose of this paper are designated Ti 115, Ti 130, and Ti 160. The principal impurity elements are given in Table I. The material was received in the form of 12.7 mm diam bars having a fully recrystallized structure. Tensile specimens with a round cross-section of 4.5 mm diam and a gage length of 15.2 mm were machined from the bars. In order to develop the same grain size (mean linear intercept of grain boundaries) in each of the three types the specimens were annealed under a dynamic vacuum of <10?5 mm Hg, Table 11. Specimen hydriding was carried out in a modified Sieverts apparatus;&apos; hydrogen was taken into solution at 450°C and after holding the specimens at this temperature for 24 hr they were furnace-cooled to room temperature at an average rate of -100 C deg per hr. By this method nominal hydrogen contents of 0, 50, 100, 250, and 500 ppm were introduced into specimens of Ti 115, Ti 130, and Ti 160 (100 ppm (wt) -0.5 at. pct). The actual hydrogen contents were calculated from the weight differences obtained by weighing the specimens before and after the hydriding treatment. Tensile tests were carried out at temperatures of -196", -78", 20°, 150°, and 300°C on a 10,000 kg In-stron machine at a nominal strain rate of -1.0 x 10-3 sec-1. Fractured specimens were sectioned in planes parallel to the tensile axis, mechanically polished to 0.25 µm grade of diamond paste, and then attack polished using a solution containing by volume 99 parts H2O, 1 part HF, and 1 part HNO3. Although the latter treatment unavoidably opened out cracks and voids visible after mechanical polishing, it did reveal the grain structure, titanium hydride morphology, and deformation twinning structure.

Jan 1, 1970

By F. M. d’Heurle

Films of molybdenum have been prepared by sputtering onto oxidized silicon substrates. The resistivity. lattice parameter, orientation, and grain size were studied as a function of substrate temperature and substrate bias. Under normal sputtering conditions, the resistivity of the films was found to be quite high (600 x 10 ohm-crn). However, with the use of the negative substrate bias of 100 v and a substrate temperature of 350°C, films weve produced with a resistivity of ahout twice that of bulk molybdenum. The lattice parameters measured in a direction nornzal to the surface of the films weve found to be gveatev than the bulk value. This was interpreted as being at least partly due to the presence of compressive stresses. The effects of annealing in an Ar-H atmosphere were studied in terms of diffraction line width, lattice parameter, and resistivity. BECAUSE of its relatively low bulk resistivity (5.6 x 106 ohm-cm)&apos; molybdenum is potentially interesting as a thin-film conductor in integrated circuits. An additional feature which makes it attractive for this purpose is its low coefficient of expansion (5.6 x KT6 per "c),&apos; which is fairly well matched to that of silicon (3.2 x 10 per c). It is possible to deposit molybdenum films by evaporation but generally films produced in this manner have a high resistivity. In order to achieve resistivities close to bulk value, Holmwood and Glang found it necessary to operate in a vacuum of about 107 Torr and to maintain the substrates at 600 C during film deposition. Sputtered molybdenum films have been examined by Belser et a1.7 and, recently, by Glang et al.&apos; This paper describes the results of an attempt to extend some of that work and examine the effects of annealing and getter sputtering on the physical and structural properties of the films produced. SPUTTERING APPARATUS AND PROCEDURE The apparatus used for most of the film sputtering work described here consisted of two "fingers" serving as anode and cathode, respectively, which were mounted within an 18-in.-diam glass chamber. A liquid nitrogen-trapped 6-in. diffusion-pump system was used to achieve a vacuum of about 1 x 107 Torr within the chamber prior to sputtering. The essential features of the equipment are shown in Fig. 1. Cathode and anode fingers are stainless-steel tubes isolated from the top and bottom plates by Teflon collars. In order to limit the discharge to the space between anode and cathode, each finger is surrounded by an aluminum hield, at ground potential, having an internal diameter 18 in. larger than the outside diameter of the finger. The cathode and anode fingers are 6 and 4 in. in diam, respectively. A 116-in.-thick sheet of molybdenum is brazed with a 10 pct Pd, 58 pct Ag, 32 pct Cu alloy to a copper disc which is mounted by means of screws and a large 0 ring onto the lower end of the cathode finger. The disc is cooled during sputtering by water circulation inside the finger. The use of several feet of plastic tubing for the water input and outputg reduces leakage to ground to less than 1 ma when the cathode potential is raised to 5 kv. The upper end of the anode finger is terminated by a brazed-on copper block. A variety of specimen holders can be easily mounted on the upper face of this block. Substrate heating or cooling is achieved by use of an appropriate unit attached to the lower face of the same block. Heating is achieved by means of cartridge-type heaters and cooling by copper coils fed with forming gas under pressure. The inner chamber of the specimen finger constitutes a small vacuum chamber of its own which is evacuated by an auxiliary mechanical pump in order to limit heating element oxidation and heat transfer by convection currents. An advantage of the finger arrangement is the absence of cooling and heating coils and wires within the main chamber. The stain less-steel shutter is useful to establish a discharge for cleaning the cathode at the beginning of each sputtering run. Water cooling of the shutter reduces heating and the out-gassing of impurities which might condense on the nearby substrates. Unless otherwise specified, the substrates used in these experiments were 1-in.-diam oxidized silicon wafe:s, 0.007 in. thick, having an oxide thickness of 6000A. The substrate holders were large copper discs onto the surface of which a number of molybdenum discs, 116 in. thick and 78 in. in diam, were brazed. The wafers were clamped to the molybdenum discs

Jan 1, 1967

By R. A. Wolfe, H. W. Paxton

Self-diffilsion coefficients for cr51 and Fe55 in 12 pct Cr-Fe and 17 pct Cr-Fe for Fe55 in chromium, and for Cr51 in vanadium have been measured. The results are compared with other values for the Fe-Cr system, and with the various theories of diffusion in hcc metals. Some empirical correlations are discussed between Do and Q in hcc systems, or, expressed differently, the constancy of ?G*/T solidus for seveval bcc metals and alloys is noted. It appears very probable that a vacancy mechanism is operative in bcc metals, hut this cannot he stated with certainty. THE great bulk of work on diffusion in metals, both experimental and theoretical, was for many years concentrated on those with close-packed and, in particular, fcc lattices.1,2 There appears to be little doubt that the mechanism of diffusion in these solids is vacancy migration, leading to mass transfer and in substitutional solid solutions to a Kirken-dall effect.3,4 For bcc metals, the picture is much less clear. The Kirkendall effect certainly occurs in several alloys.5-10 However, attempts to understand the factors contributing to the pre-exponential in the usual expression for the diffusion coefficient D =D, exp {-Q/RT) by extension of ideas useful in close-packed lattices have not always been successful. Zener,11 Leclaire,12 and Pound, Paxton, and Bitlerl3 have suggested that various forms of ring diffusion may be important in some bcc metals. For close-packed metals, Do is usually about 1 sq cm per sec and Q - 35Tm kcal per mole (Tm = melting temperature in OK). The theory of Pound et al. suggests for ring diffusion that Do may be about 10-4 and Q, although difficult to calculate with any precision, would be significantly less than 35 T,. The experimental results on self and solute diffusion in ? uranium14,15 and ß zirconium,10 and for solutes in 0 titanium,17 and possibly for self-diffu- sion in chromium below about 0.75 T,," gave some credence to this theory. However, not all bcc materials display low values of DO and Q, and the exceptions were not predicted by any theory. Furthermore, it has recently become apparent that, in bcc materials, log D is not always linear with T-l if a sufficiently wide range of temperature is studied.16,18 This variation may be such that Q may increase18,19 or decrease20 with increasing temperature. The present work was undertaken in an attempt to provide further diffusion data on bcc metals, and to try to understand the factors which contribute to differences in behavior between the various elements. For part of this work, the Fe-Cr system was chosen since it is of considerable technological importance, and data on 12 pct Cr and 17 pct Cr alloys appeared well worthwhile to supplement that existing for the remainder of the stern.18,22 The diffusion of Fe55 in chromium was studied as an example of a more or less "normal" tracer element in a possibly abnormal host lattice. Finally, no data were available for vanadium, the neighbor of chromium in the periodic table, because of lack of a suitable isotope so cr55 was used as a tracer in a few preliminary experiments. For convenience, we shall refer to elements whose Do and Q are low compared to those predicted by Zener&apos;s theory as "anomalous". PROCEDURE This investigation determined self-diffusion rates by means of radioactive tracers and the integral-activity method first utilized by Gruzin.23 In this method a thin layer of radioisotope of the diffusing element is plated or coated onto a planar surface of the diffusion sample, which is then given an isothermal-diffusion annealing treatment. The determination of an activity-penetration curve involves measuring the residual activity of the specimen after each successive layer or section has been removed parallel to the original planar surface. The method used here is essentially the same as that used by Gondolf18 and Kunitake.21 Two radioactive tracers, cr51 and Fe55, were used in this investigation. Diffusion coefficients were determined for the diffusion of one or both of these tracers in four different materials, viz., Fe-12 wt pct Cr alloy, Fe-17 wt pct Cr alloy, chromium, and vanadium. The diffusion samples had nominal dimensions of 1.5 cm diameter and 0.5 cm thickness. The grain size was several millimeters for the Fe-Cr alloys and at least 1 mm for the chromium and vanadium samples. Accurately planar surfaces

Jan 1, 1964

By F. I. Grace, L. E. Murr

The mechanical responses and residual defect structures in 70/30 brass and type 304 stainless steel following explosive shock loading and cold reduction by rolling have been studied. A distinct relationship was observed to exist between the residual mechanical properties and micro structures observed by transmission electron microscopy. Shock-loaded brass deformed primarily by the formation of coplanar arrays of dislocations and stacking faults at lower pressures, and twin-faults (deformation twins and €-martensite bundles) at higher pressures (> 200 kbar). The micro -structures of cold-rolled brass were characterized by dense dislocation fields elongated in the rolling direction. Stainless steel was observed to deform by the formation of dense arrays of stacking faults at lower shock pressures and twin-faults at high shock pressures (>200 kbar). Lightly cold-rolled stainless steel deformed similar to low Pressure shock-loaded stainless steel, but transformed to a&apos; martensite in heavily cold-rolled stainless steel. Discontinuous yielding was observed for the heavily cold-rolled stainless steel, and stress reluxution in the weyield region for cold-rolled and shock -loaded stainless steel was interpreted as an indication of the ability of twin-faults and stacking faults to act as effective barriers to dislocation motion. A simple model for the formation of the planar defects and a&apos; martetnsite is presented based on the propagating of Shochley partial and half-partial dislocations. A considerable effort has been expended over the past decade in an attempt to elucidate the response of metallic-crystalline solids to the passage of a high velocity shock wave (e.g., smith,&apos; Dieter,2 and zukas3). While it has been possible to obtain relevant information pertaining to the residual defect structures and mechanical properties, there have been few rigorous attempts to draw a direct comparison between these structures and properties. In addition, numerous investigators have recently observed the occurrence of deformation twinning in shock deformed fcc metals (e.g., Nolder and Thomas,4 and Johari and Thomas5), but little attempt has been made to elucidate the mechanisms of formation of these defects. Comparative data for metals deformed by shock-loading and the same metals deformed by more conventional modes of deformation such as cold-reduction by rolling is also generally lacking. The present investigation therefore has the following objectives: 1) to examine the mechanical properties of some explosively shock loaded and cold-rolled fcc metals of low stacking-fault energy as a function of their residual substructures; 2) to present a simple model for the formation twin-faults and related defect structures in the low stack-ing-fault energy materials of interest (70/30 brass, ySFg= 14 ergs per sq cm; and 304 stainless steel, ySF = 21 ergs per sq cm); 3) to make some deductions with regard to the residual characteristics of dislocation and planar defect substructures in cold rolled and shock loaded 70/30 brass and type 304 stainless steel. In particular, it was desirable to characterize the residual hardening effects of particular deformation substructures. I) EXPERIMENTAL PROCEDURE Sheet samples of 70/30 brass (0.005 and 0.15 in. thick; annealed at 659°C for 2 hr) and type 304 stainless steel (0.007 in. thick; annealed 0.25 hr at 1060°C) of nominal compositions shown in Table I were cold-rolled in one direction only to produce reductions in thickness of 15, 30, 45, 60, and 75 pct in the brass; and 5, 15, 25, 35, and 45 pct in the stainless steel. Identical sheet samples in the annealed (unrolled) state were subjected to plane compressive shock waves to various peak pressures ranging from 0 to 400 kbar in the brass and 0 to 425 kbar in the stainless steel; and with a constant peak pressure duration of approximately 2 microseconds. A detailed description of the shock loading technique has been given previously.6 Tensile specimens 1.0 in. in length and 0.125 in. in width were cut from the cold-rolled sheets (tensile axis parallel to the rolling direction), and the shock-loaded sheet specimens. Stress (load)-strain (elongation) measurements on the tensile specimens were made on a Tinius-Olsen load-compensating tensile tester using a strain rate of 2.7 x 10-3 sec-1. Tensile tests were repeated at least twice, giving essentially the same results. Stress relaxation measurements in the preyield region were also made using an initial strain rate of 5.4 x 10-4 sec-1. In addition to tensile and stress relaxation measurements, Vickers microhardness measurements were made on all samples. A total of 100 microhard-ness readings were obtained for each specimen following a light electropolish to ensure uniform surface conditions for all tests. The hardness averages ob-

Jan 1, 1970