Journal of the Japan Institute of Metals and Materials
Online ISSN : 1880-6880
Print ISSN : 0021-4876
ISSN-L : 0021-4876
Volume 33 , Issue 8
Showing 1-20 articles out of 20 articles from the selected issue
  • Zenji Nishiyama, Ken’ichi Shimizu, Masayuki Harada
    1969 Volume 33 Issue 8 Pages 871-877
    Published: 1969
    Released: April 04, 2008
    JOURNALS FREE ACCESS
    Transmission electron microscope observation has been made on the martensite of Fe-10.3%Al-1.50%C steel, with the following results: (1) The martensite gives the diffraction pattern of a body-centred tetragonal lattice with extra spots. These spots are coincident in position with those of the lattice produced by the Bain distortion from the parent lattice which was assumed to be of the Cu3Au type; (2) it has fine twin faults and stacking faults of the {112} type and not of the {211} type; and (3) the martensite crystals are generally wedge-shaped but some of them have a lamellar structure which consists of two variants having the c-axes approximately perpendicular to each other.
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  • Masaiti Hori
    1969 Volume 33 Issue 8 Pages 878-882
    Published: 1969
    Released: April 04, 2008
    JOURNALS FREE ACCESS
    Tempering transformations of Cu-Al-Be-4Fe alloys were studied by means of specific heat measurements. The results obtained were as follows: (1) The microstructures of quenched Cu-Al-Be alloys were β1. Tempering processes of quenched Cu-Al-Be alloys were precipitations of α or γ2 and β1→β. But the abnormal phenomena took place at about 250°C in a hypo-eutectoid alloy. (2) The microstructure of the quenched hypo-eutectoid Cu-Al-Be-4Fe alloy was β′ martensite. Tempering processes of the hypo-eutectoid Cu-Al-Be-4Fe alloy showed abnormal phenomena at about 300°C, β′→β1, precipitations of α, β1→α+γ2+κ, β1→β, β→α+γ2+κ and α+γ2+κ→β. (3) The microstructures of quenched hyper-eutectoid Cu-Al-Be-4Fe alloys were β1. Tempering processes of hyper-eutectoid Cu-Al-Be-4Fe alloys were precipitations of γ2, β1→β, β→α+γ2+κ and α+γ2+κ→β in the lower Be alloy, but became β1→β after the precipitation of α in the higher Be alloy.
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  • Toshimasa Morooka, Eiji Yuasa
    1969 Volume 33 Issue 8 Pages 883-888
    Published: 1969
    Released: April 04, 2008
    JOURNALS FREE ACCESS
    The effect of warm-drawing conducted during the age-treatment at various temperatures on the subsequent ageing of industrial Al-Mg-Si (63S) and Al-Zn-Mg (75S) alloys was examined. Further, the variations in hardness and structures of the alloys, when aged ordinarily, aged after the cold-drawing and aged after the warm-drawing, were observed. In the case of alloy 63S, the results are as follows: (1) When warm-drawing is conducted after pre-ageing, the maximum hardness obtained is higher and the ageing time for this is shorter in the subsequent ageing than in the cases of cold-drawing and the ordinary ageing. These tendencies become remarkable with increasing time of pre-ageing. (2) The electron-microscopic observation of the warm-drawn specimen reveals fibred sub-grains and tangled dislocations of high density. When re-ageing is conducted subsequently, some dislocations disappear and most of the remaining dislocations form a cell-boundary. (3) The type of age-hardening changes from the precipitation type into the pseudo-precipitation one by cold- or warm-drawing. In the case of alloy 75S, the results are: (1) The hardness is increased by the warm-drawing after pre-ageing at 80°∼140°C, but the reverse is the case when re-aged at a higher temperature than that of the warm-drawing. (2) When re-aged after warm-drawing, the maximum hardness is higher than that in the other cases. (3) According to electron-microscopic observations of the warm-drawn specimen, the precipitates form an intermediate M′ phase in sub-grains or at boundaries, the number of the precipitates being larger than those in other cases.
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  • Isao Gokyu, Takehito Nomura, Yoshiharu Mae
    1969 Volume 33 Issue 8 Pages 889-893
    Published: 1969
    Released: April 04, 2008
    JOURNALS FREE ACCESS
    The Kocks method is known as a method of rolling wire rods by the three-roll system with a slight tension, but the concrete rolling conditions, such as the effects of the size and the shape of billets and the rolling tension on the reduction in area and the shape of the wire rod after rolling, are not available.
    The authors carried out rolling tests using Plasticine as a modelling material of steel in hot working. The results show that if the size and the shape of billets before rolling are known, the shape of billets after rolling and reduction in area can be determined at every rolling tension, and thus it has become possible to decide the most appropiate rolling pass schedule of the three-roll system.
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  • Ishi Miura, Susumu Hirano
    1969 Volume 33 Issue 8 Pages 894-898
    Published: 1969
    Released: April 04, 2008
    JOURNALS FREE ACCESS
    The tensile properties of Al and Sn reinforced by E-glass fiber and SiO2 glass fiber were investigated. These composites were fabricated by the vacuum hot press process, using the foil metallurgy technique(1). The quantity of the glass fiber is up to 40 vol% in Al and up to 20 vol% in Sn. The conditions for pressing were as follows; 2 hours at 600°C in Al composites and 5 hours at 200°C in Sn composites under a pressure of 420 kg/cm2.
    The composites reinforced by SiO2 glass fiber are more strengthened than that of E-glass fiber in Al and Sn, because of the difference in heat resistivity between the two kinds of glass fibers. And the Sn composites are also more strengthened than the Al composites. These results seem to be mainly due to the strength decrease in glass fiber, since no interaction between fiber and matrix has been observed by electron probe micro-analysis and microscopic examination and no fiber damages have been found during the fabrication. Moreover the relationship between the shear stress of matrix, τm and critical aspect ratios has been discussed.
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  • Ôhiko Kammori, Isamu Taguchi, Akihiro Ono
    1969 Volume 33 Issue 8 Pages 899-904
    Published: 1969
    Released: April 04, 2008
    JOURNALS FREE ACCESS
    For quantitative extraction of niobium carbide from low carbon niobium steel, comparisons were made on the acid extraction method (6 N HCl or 30 N H3PO4) without stirring at room temperature, the acid extraction method under ultrasonic stirring at room temperature, the acid extraction method by heating, the potentiostatic electrolysis extraction method with 15%Na-citrate-1.2%KBr electrolyte (pH 3, adjusted with citric acid), the potentiostatic electrolysis extraction method with 5%Na-citrate-1.2%KBr electrolyte (pH 5, adjusted with citric acid) and the potentiostatic electrolysis extraction method with 7%HCl-3%FeCl3-Ethylene-glycol electrolyte were compared.
    The potentiostatic electrolysis extraction method with 15%Na-citrate-1.2%KBr electrolyte (pH 3, adjusted with citric acid) was recommended, because of the highest extraction ratio of niobium carbide and the least dependence of the extraction of niobium carbide upon electrolytic potential.
    The steel sample (50×25×5 mm) is suspended as an anode in about 1.3 L of 15%Na-citrate-1.2%KBr electrolyte adjusted to pH 3 by citric acid. From 0.1 to 2 g of the sample is potentiostatically electrolyzed at −400 mV vs SCE under nitrogen atmosphere. The residues attached to the sample and those in the anode cell electrolyte are collected through a Millipore filter. Niobium in the residues is determined by iso-amyl-alcohol-extraction-molybdenum-blue spectrophotometry and calculated as niobium carbide.
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  • Kenzo Igaki, Nobumitsu Ohashi, Seiichi Takaki
    1969 Volume 33 Issue 8 Pages 904-910
    Published: 1969
    Released: April 04, 2008
    JOURNALS FREE ACCESS
    Three sources of iron have been purified by floating-zone refining, the dry H2 treatment, the wet H2 treatment and the vacuum treatment, and the effects of purification have been discussed. Using the iron specimens with different purities, the effects of various measuring conditions on the electrical resistivity and the longitudinal magnetoresistance effect up to a field of 1000 Oe have been investigated at 4.2°K. The conditions of electrical resistivity measurements which are suitable for specifying the purity of iron have also been considered. The results obtained are summarized as follows.
    (1) High-purity iron with the resistivity ratio RRR{=ρ(298°K)⁄ρ(4.2°K)} of 465 [RRRmin{=ρ(298°K)⁄ρmin(4.2°K)}=2200, Δρ⁄ρ=−84%] has been obtained from the source of iron with the least metallic impurities (Johnson-Matthey iron) by the wet H2 treatment (30%H2O-H2) after floating-zone refining.
    (2) The electrical resistivity of purer iron is more influenced by the measuring current.
    (3) The longitudinal magnetoresistance of pure iron reaches the minimum value (ρmin) at an applied magnetic field of 700∼800 Oe. The value of ρmin is independent of the measuring current density in the range of 50 to 150 A/cm2 and is not influenced by the condition of demagnetization and the earth’s magnetic field. RRRmin obtained with ρmin shows more clearly the difference in the purity of iron. The modified resistivity ratio RRRmin can be used as an appropriate index of purity for iron.
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  • Masahiro Kitada, Shigeyasu Koda
    1969 Volume 33 Issue 8 Pages 911-916
    Published: 1969
    Released: April 04, 2008
    JOURNALS FREE ACCESS
    The oxidation phenomena of thin films of the reactor-grade pure zirconium and the behavior of thin films of produced zirconia were investigated by means of transmission electron microscopy. The oxidation of zirconium is carried out by electron beam heating in the electron microscope. The results are as follows:
    (1) When the specimen is heated gradually, small grains of monoclinic zirconia at first appear in a wide range of the thin film, and then, as a result of the increase in grain number and grain growth, the thin film of zirconium is entirely oxidized. Preferred oxidation near the grain boundary of zirconium is also observed. On the other hand, when the thin film of zirconium is heated strongly, the thin film changes rapidly to the pseudo-amorphous oxide at first, and then the monoclinic zirconia nucleates in the pseudo-amorphous oxide and grows into large grains.
    (2) When the thin film of zirconium is oxidized instantaneously in air, the thin film changes into the monoclinic zirconia with a grain size of about 0.3 to 0.5 μ diameter.
    (3) In the tetragonal zirconia, an active movement of dislocations and the presence of movable dislocation loops are observed.
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  • Takuro Kobayashi, Toshihiro Matsumoto
    1969 Volume 33 Issue 8 Pages 916-921
    Published: 1969
    Released: April 04, 2008
    JOURNALS FREE ACCESS
    To investigate the effect of welding residual stresses on the fatigue strength, the mild steel specimens were localy flame-heated and cyclic stressed. The change in residual stresses on the surface of the specimen due to cyclic stressing was determined by the X-ray diffraction method.
    The fatigue life of the flame-heated specimen was shorter than that of the annealed specimen at high stress amplitudes, while the fatigue limits of the both were almost similar.
    The longitudinal residual stresses near the flame-heated zone of the flame-heated specimen were tensile and those near the side end of the specimen were compressive. These residual stresses underwent changes in the following three stages by cyclic stressing; the residual stresses decreased rapidly in the early stage (first stage), slightly increased at about 0.1 fatigue ratio (nN) (second stage) and then decreased gradually (third stage).
    Large surface strain was seen near the maximum tensile residual stress zone after cyclic stressing. Yield phenomena accelerated with the addition of residual tensile stress to the mean applied stress are thought to cause the shortening of the fatigue life of the flame-heated specimen at a high amplitude of stress.
    The microstructures generated with flame-heating did not contribute to the lowering of fatigue strength of mild steel.
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  • Atsushi Takei, Hiroko Takaishi
    1969 Volume 33 Issue 8 Pages 922-927
    Published: 1969
    Released: April 04, 2008
    JOURNALS FREE ACCESS
    For the purpose of studying the effects of additions of small amounts of elements on high temperature oxidation of 80Ni-20Cr alloy, the oxidation behaviors of four kinds of alloy containing 1, 0.1 and 0.01%Al and without Al were studied, following the previous report on the effects of small amounts of Be.
    The oxidation tests were carried out mainly by the repeated heating method over the temperature range from 900°C to 1200°C in the atomosphere. The oxidation products on these alloys were observed by means of metallography, X-ray diffraction, electron diffraction and electron probe microanalysis.
    From these experimental results, it was found that the addition of 1%Al is effective to the prevention of high temperature oxidation, because it decreases the oxidation rate and prevents the spalling of the protective oxide layer during the heating and cooling cycle, although it was not better than the case of 0.1%Be. The oxidation resistance of 0.1 and 0.01%Al alloys were rather inferior to non-Al alloy. After the oxidation tests, the 1%Al alloy forms an oxide layer composed mainly of Cr2O3 and also a subscale that has a component of Al oxide. The present results were similar to the results on 0.1%Be alloy.
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  • Tsuyoshi Masumoto, Yunoshin Imai
    1969 Volume 33 Issue 8 Pages 927-933
    Published: 1969
    Released: April 04, 2008
    JOURNALS FREE ACCESS
    The solid phase reactions in the iron-rich corner of the quaternary Fe-Cr-C-N system were considered based on the phase diagrams of ternary systems and quaternary systems at fixed contents of 7, 12, 18 and 25% chromium. In the Fe-Cr-C-N system, it was assumed that the nonvariant reactions concerned in the iron-rich corner can be expressed as follows:
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  • Masaru Satoyoshi, Fusao Hayama
    1969 Volume 33 Issue 8 Pages 934-938
    Published: 1969
    Released: April 04, 2008
    JOURNALS FREE ACCESS
    An experimental study has been made of the effects of humidity on the dry friction of metals. The sliding friction test was carried out in the atmosphere of a constant temperature (30°C) and a constant humidity (dry and relative humidity 80%).
    Wear of iron slid against a hardened bearing steel ring under a load of 1 kg decreased sharply, when water vapour was contained in the atmosphere, particularly at a lower sliding speed. However, at a higher sliding speed (4 m/sec), no difference was observed in the wear of iron between the cases slid in dry atmosphere and in humid one. Wear of iron at 1 m/sec decreased with increasing water vapour pressure in the atmosphere.
    Wear of 70/30 brass decreased in the presence of water vapour at a lower sliding speed, as in the case of iron.
    However, in the case of leaded 60/40 brass which showed a severe wear, the presence of water vapour increased the friction and wear.
    It was observed that in the friction of iron or 70/30 brass, fine wear debris cohered together and adhered to the frictional surface, and the presence of water vapour accelerated the cohesion and adhesion of wear debris to the surface. It is suggested that the fine wear debris (oxides) adhered to the metal surfaces protects the surfaces from metallic adhesion and reduces the wear.
    A large wear debris was formed in the case of leaded 60/40 brass, and it appears that the adhesion of wear debris to the sliding surface increased by water vapour causes an increase of friction and wear.
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  • Hidehiro Goto, Minoru Hosoya
    1969 Volume 33 Issue 8 Pages 939-943
    Published: 1969
    Released: April 04, 2008
    JOURNALS FREE ACCESS
    Determination of oxygen in ferrosilicon was attempted by the argon-carrier fusion method, using carbon powder wrapped in tin foil as a bath.
    With the powder sample, an unreasonably higher value was obtained than a mean value of real and original oxygen contents because the oxygen content on the surface contributes the measured value more domnanthly with the increase in surface area.
    For an accurate analysis of the block sample, it is essential to obtain a mean value of oxygen contents by sampling from as many parts of the block sample as porsible, or at least from the upper, middle, and lower layers of the sample, though in the latter case it is required to specify the sampling position with the analytical results.
    By the proposed method, the complete reduction of oxides is accomplished with a block sample and the determination of oxygen can be repeated with several samples for each bath.
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  • Tomomi Mizuno, Tetsuo Matsumura
    1969 Volume 33 Issue 8 Pages 944-948
    Published: 1969
    Released: April 04, 2008
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    The determination of several metallic impurities in titanium is difficult and time-consuming by chemical methods. A direct spectrographic method was developed for the simultaneous determination of aluminum, chromium, copper, iron, manganese, molybdenum, silicon, tin, vanadium, and zirconium in titanium.
    The procedures are based on low voltage spark (Multisource type) excitation of solid samples in combination with 90° cone graphite rod as a counter electrode. The spectra are recorded through a 3.4 meter Ebert mount grating spectrograph and measured in accordance with conventional spectrochemical practices. The measured transmittances for the spectral lines are converted to relative intensities, which are referred to analytical curves to obtain the elemental concentrations.
    The sensitivity of this method is good and the precision is satisfactory for a routine quantitative method. This method has been applied for over two years to melting process control without any troubles.
    The X-ray fluorescence method has also been investigated as compared with the emission spectrographic method.
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  • Kazuo Kawamura, Shiro Watanabe, Masahiro Yamada
    1969 Volume 33 Issue 8 Pages 949-953
    Published: 1969
    Released: April 04, 2008
    JOURNALS FREE ACCESS
    The experiment was conducted to establish an accurate separation and determination method for Al2O3 inclusions co-existing with AlN in steels.
    Three kinds of specimens were prepared so that the contents of Al and N were Al<N, Al=N, and Al>N in atomic ratio, respectively. These were tempered at 600°∼900°C after solution treatment at 1300°C.
    The samples were submitted to analytical methods by I2-CH3OH, Br2-CH3CO2CH3, and acids, respectively, to determine AlN and Al2O3 contents, and furthermore to electron microscopic observation to clarify the relation between the precipitation and the chemical behavior of AlN. The oxygen contents were comfirmed to be a range of 20∼30 ppm for each sample, thus indicating the presence of definite amounts of Al2O3 inclusions.
    The experimental results showed that the AlN values by I2-CH3OH method were lower than those by Br2-CH3CO2CH3 method as for the samples [Al>N] and [Al=N]; the former values were 30∼90% of the latters. These differences were proved to be based on the presence of some AlN which was decomposed by CH3OH, and correspondence was observed between the precipitation forms and the chemical behavior of AlN.
    Therefore, it is improper for correction of the Al2O3 value by I2-CH3OH method to use, as usual, the AlN value by Br2-CH3CO2CH3 method. In case of co-presence of AlN it was comfirmed that the Al2O3 inclusions are most effectively determined by HNO3(1+5) dissolution method.
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  • Kazuo Kawamura, Shiro Watanabe, Tokio Suzuki
    1969 Volume 33 Issue 8 Pages 954-958
    Published: 1969
    Released: April 04, 2008
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    The chemical behaviour of molybdenum carbides were studied, in an attempt to establish a phase analytical method for them, of the steels of Fe-Mo-C system which were subjected to heat treatment to precipitate molybdenum carbides M3C, Mo2C, M23C6, and M6C.
    Molybdenum carbides were chemically less stable than carbides of vanadium, niobium, and titanium as to be dissolved to some extent even by H2O, CH3OH or C2H5OH. Their chemicalstabilities were found to increase in the following order M3C M23C6 M6C Mo2C.
    The quantitative extraction of all the molybdenum carbides was achieved by 9 N-H2SO4 dissolution at room temperature, but low results were obtained by other methods.
    As regards the separation and the determination of Mo2C, the satisfactory results were obtained in case of co-existence with M3C either by 9 N-H2SO4 dissolution HCl·CH3OH treatment or by 30 N-H3PO4 dissolution, but only the approximate values were obtained when Mo2C was co-present with M23C6 and M6C.
    The following points were clarified by the experiments;
    (1) M3C was not stable towards H2SO4, H3PO4, and HCl.
    (2) Mo2C was stable towards H2SO4 and H3PO4.
    (3) M23C6 was stable towards H2SO4, but not towards H3PO4 and HCl.
    (4) M6C was stable towards H2SO4 and H3PO4, but not towards HCl.
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  • Mitsunori Sato, Masayuki Hijikata, Ichiro Morimoto
    1969 Volume 33 Issue 8 Pages 959-964
    Published: 1969
    Released: April 04, 2008
    JOURNALS FREE ACCESS
    The structure and composition of migrated layer formed on the surface of internally oxidized Ag-CdO contacts were observed by an electron probe X-ray microanalyser and a microscope. Changes in welding resistance and contact resistance with growth of the migrated layer were also measured.
    The results obtained are as follows:
    The migrated layer formed by switching the d.c.circuit is deposited in the form of a laminar structure which consists of Cd-and Ag-rich phases on the contact surface. The amount of Cd in the migrated layer depends on the Cd content in the anode materials, and is hardly influenced by the circuit condition. As the current flows through the migrated layer, the contact resistance increases and the welding resistance remarkably decreases with increasing Cd content. In this case, the direction of material transfer is from anode to cathode, so that the migrated layer is made on the cathode contact surface. The welding resistance and the contact resistance are therefore influenced by anode materials.
    On the other hand, the migrated layer formed by switching the a.c. circuit is not in the form of a laminar structure and, moreover, it deposits around the contact area. Therefore, the welding resistance and the contact resistance are hardly influenced by the migrated layer.
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  • Kôichi Arai
    1969 Volume 33 Issue 8 Pages 965-970
    Published: 1969
    Released: April 04, 2008
    JOURNALS FREE ACCESS
    A kinetic study of the aqueous oxidation of ZnS in dilute HCl solution has been made in order to obtain foundamental data of the acidic leaching condition.
    Deaerated HCl solution of pH 1∼3 and 10−1∼1 M/L Cl is used as the acidic medium. The amount of ZnS suspended in the solution is 10−2∼10−1 M/L.
    The solution is maintained at a constant temperature between 25°∼30°C and stirred at 600 rpm.
    The experimental results obtained are as follows:
    (1) The main dissolution reaction of ZnS in the acidic solution is a type of H2S formation and shows a parabolic dissolution behavior.
    The reaction is diffusion control.
    (2) The effect of pH on the dissolution rate of ZnS is linear and the rate of dissolution decreases as the value of pH increases.
    (3) The presence of Cl ion acts on the dissolution of ZnS, especially at high temperatures.
    (4) The relation between the dissolution rate of ZnS and the surface area of ore suspended in the solution is linear. Its rate increases propotionally with increasing area of the ore.
    (5) The dissolution of ZnS is large at first and then decreases with the lapse of time. The decreasing rate of dissolution of ZnS is probably due to the increase of Zn2+ in the solution.
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  • Hideo Abe, Kazumasa Togano
    1969 Volume 33 Issue 8 Pages 970-975
    Published: 1969
    Released: April 04, 2008
    JOURNALS FREE ACCESS
    Several authors have reported that when a metal is solidified from the flowing liquid its columnar axis tilts from the normal direction of the chilled plane to the upstream. In the present study the textures of the columnar regions in Al-0.3%Cu and Al-3%Cu alloy ingots solidified from the flowing liquids were investigated by the X-ray pole-figure method. The molten alloy flowed in a channel composed of a water-cooled copper plate and isolite walls. (200) and (220) pole figures were determined on the sections at several distances from the chilled plane of the solidified layer.
    The columnar axis of Al-0.3%Cu alloy is parallel to the [100] direction, while that of Al-3%Cu alloy tilts 10° more than the [100] preferred direction to the upstream. The textures of the columnar regions in both alloys are not simple fiber textures observed in the normal ingots. In Al-0.3%Cu alloy, the intensity maxima in the (220) pole figure correspond to the (100)[011] orientation rotated 15° about the transverse direction from the normal of the chilled plane to the columnar axis. Where, (100)[011] means that (100) is parallel to the chilled plane and [011] is parallel to the flow direction of the melt. In Al-3%Cu alloy, the intensity maxima correspond to the (100)[001] orientation rotated 15° about the transverse direction from the normal of the chilled plane to an axis 10° from the columnar axis.
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  • Hiroshi Hirano, Masatoshi Sudo, Yoshiyuki Yutori
    1969 Volume 33 Issue 8 Pages 975-983
    Published: 1969
    Released: April 04, 2008
    JOURNALS FREE ACCESS
    This investigation has been carried out to make clear the effect of strain rates and pre-strains on the mechanical properties and the phase transformation of Austenitic stainless steel at diverse temperatures. The formation of martensite is examined by X-ray diffraction, specific gravity and permeability measurements and transmission electron microscopy.
    The main results obtained are as follows:
    (1) The tensile strength at room temperature which increases not only at high strain rate but also at low strain rate, shows the lowest value at the strain rate \dotε=4×10−2. But the flow stress increases linealy with strain rate. The reduction in area decreases with increase in strain rate.
    (2) The mechanical properties at low temperatures are influenced by chemical compositions and show unique behaviors. Chemical compositions and strain rates give a remarkable effect on the amount of martensite formed with plastic deformation. The degree of martensite formation decreases with increase in strain rate.
    (3) Stainless steel pre-strained at room temperature shows the “plateau” similar to Lüders band in the stress-strain curves at −196°C. The length of the plateau depends on the amount of the prestrain at room temperature.
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