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Volume 36, Issue 12
Displaying 1-17 of 17 articles from this issue
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Toshiya Hirata, Shigeru Matsuo1972 Volume 36 Issue 12 Pages 1159-1163
Published: 1972
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe effect of plastic deformation after quenching on the precipitation in an Al-Mg-Si alloy has been investigated by means of hardness and specific heat measurements and electron microscopy. The major results obtained are as follows:
(1) It was found that the plastic deformation after quenching accelerats the age-hardening processes at 200°C and the obtained maximum hardness is higher than in the specimen aged without plastic deformation.
(2) The intermediate β′ and stable β phases are formed at lower temperatures in the plastically deformed specimen after quenching. The activation energy for the formation of the intermediate β′ phase in the plastically deformed specimen was determined to be about 28 kcal/mol.
(3) The density of precipitates in the specimens aged at 200°C for 67 hr increased with the amount of strain after quenching. This was considered to be attributable to a heterogeneous nucleation on dislocations and the acceleration of diffusion in terms of the nucleation theory.
(4) The precipitate β′ nucleates on subgrain boundaries in the specimen aged at 270°C for 46 hr after 25% reduction in thickness by rolling after quenching.View full abstractDownload PDF (2542K) -
Masanori Murakami, Masao Kikuchi, Osamu Kawano, Yotaro Murakami1972 Volume 36 Issue 12 Pages 1164-1167
Published: 1972
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn previous work the method for determination of the solvus temperature of G.P. zones in a binary Al-Zn alloy by means of the X-ray small-angle scattering method was described. Also, it was shown that the determined solvus temperature coincided with the results obtained by electrical resistivity and transmission electron microscopy experiments. In the present paper the small-angle scattering method was used to determine the solvus temperatures of the zones for Al-6.8 at%Zn alloys containing 0.1 at%Ag, Si and Mg, respectively. It was found that the addition of Ag or Mg increased the solvus temperature of the binary alloy, but Si had no remarkable effect on it. These results were discussed in terms of the interaction between these third elements and the Zn and Al atoms.View full abstractDownload PDF (1155K) -
K\={o}z\={o} Nakazawa, Masahiko \={O}tsuka, S\={o}kichi Umekawa1972 Volume 36 Issue 12 Pages 1168-1173
Published: 1972
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe effects of annealing and subzero treatment on thermal dilatation of the W-fiber Cu composite were studied in relation to the residual stress and matrix yielding.
For the composite annealed at 600°C for 1 hr, the heating curve forms a hysteresis loop with the cooling curve on the test up to 300°C, and a small region of inflection is observed on each curve.
By the subzero treatment at −196°C for 10 min the inflection temperature on heating is lowered, but on cooling, it remains unchanged and no hysteresis loop is formed.
In the temperature range which reaches the inflection region on heating and cooling tests, the fiber and the matrix undergo elastic deformation. The matrix begins to yield at the inflection. On the heating curve of the subzeroed composite, the inflection region is observed near room temperature corresponds to the matrix yielding.
The temperature dependencies of expansion and contraction within the temperature range from the start to the inflection on heating and cooling tests below 300°C become smaller with increasing volume fraction of fiber (Vf). The coefficient can be simply estimated by the stress condition.
The expansion coefficient beyond the temperature, at which the matrix starts the yielding, is independent of Vf and corresponds to the coefficient of the fiber. The average of the coefficient up to 300°C becomes smaller with the increase of Vf and coincides with the calculated value.View full abstractDownload PDF (2143K) -
Sen-ichi Yamada, Noboru Komatsu1972 Volume 36 Issue 12 Pages 1173-1179
Published: 1972
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn the internal oxidation of Cu-1%Al alloys, the oxidation rate and the effect of the alloying elements on the formation of dispersion particles were studied.
Four elements, Ag, Pd, As and In, were selected as the alloying elements. The former two elements have lower absolute values of free energy of oxide formation than Cu. The latter two have the values higher than Cu but lower than Al. Cu-1%Al alloys containing 0.5∼1.5% of the alloying elements were investigated by electron microscopy and the X-ray diffraction method. The following results were obtained;
(1) The alloys containing Ag, Pd or As showed almost the same rate of internal oxidation as Cu-1%Al alloy. But the rate of the In-containing alloy was much slower than that of the Cu-1%Al alloy. The internal oxidation did not proceed deeper than 30 μ from the surface with the alloy in excess of 1%In.
(2) In the alloys containing Ag, Pd or As granular α-Al2O3 and γ-Al2O3 of 300∼600 Å in size were formed by internal oxidation, while In2O3 was formed in the In containing alloy.View full abstractDownload PDF (4032K) -
Keijiro Nakasa, Hideo Takei, Tetsuhiro Asamoto1972 Volume 36 Issue 12 Pages 1180-1188
Published: 1972
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe effect of delayed failure on the fatigue crack propagation rate in water of Ni-Cr-Mo martensitic steel was investigated. The results obtained are as follows:
(1) The relation between the fatigue crack propagation rate da⁄dN in air and the stress intensity factor range ΔK is expressed as da⁄dN=C1(ΔK)m1, and m1 increases with increase of Km⁄ΔK, where Km is the mean stress intensity factor.
(2) The relation between the crack propagation rate da⁄dt in delayed failure and the static stress intensity factor KD is expressed as da⁄dt=C2(KD)m2.
(3) The fatigue crack propagation rate (da⁄dN)w in water is expressed as the addition of both fatigue crack propagation rate in air and crack propagation rate in delayed failure, and the following equation holds:
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where f is the frequency (cpm); β is a coefficient of addition and depends mainly on f and Km⁄ΔK. Under the condition in this experiment (f=55∼345 cpm, Km⁄ΔK=0.5∼4), β is 0.2∼0.4.
(4) Physical meaning of β is considered to be the ratio of the time in which the tri-axial tensile stress state region at the crack tip meet a cluster of hydrogen atoms during one cycle.View full abstractDownload PDF (3959K) -
Hiroyasu Mitani, Masaru Yokota1972 Volume 36 Issue 12 Pages 1189-1195
Published: 1972
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn a previous paper(1) we have already reported that the addition of nickel powder to the Cu-γ2(Cu9Al4) mixed powder compact reduced the expansion of the compact during sintering.
By using chemically nickel plated copper or γ2 composite powders, in the present study we carried out a more detailed examination of the sintering process for mixed powder compacts of the Cu-γ2-Ni system in order to improve the distribution of nickel in the compacts.
The results obtained were as follows:
(1) The Cu-(γ2-Ni) mixed powder comact expanded comparatively during sintering. However, the (Cu-Ni)-γ2 mixed powder compact shrinked remarkably during sintering, where (A-Ni) denotes the chemically nickel plated A-powder.
(2) Homogenization at a given sintering condition proceeds more rapidly in the mixed powder compact of (Cu-Ni)-γ2 than in the Cu-(γ2-Ni) mixed powder compact.
(3) The above differences in the dimensional changes and the homogenization process between the (Cu-Ni)-γ2 and the Cu-(γ2-Ni) mixed powder compacts were explained on the basis of unequal interdiffusion of each element: if the mass of A-atoms diffused into the B-particles is the (MA)B, (MAl+MNi)Cu≅(MCu+MNi)γ2, in the (Cu-Ni)-γ2 system and (MAl+MNi)Cu<(MCu+MNi)γ2 in the Cu-(γ2-Ni) system.View full abstractDownload PDF (2317K) -
Masami Onishi, Yoshinori Wakamatsu, Terunori Sasaki, Manabu Sagara1972 Volume 36 Issue 12 Pages 1196-1201
Published: 1972
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSFormation kinetics of intermetallic compounds in Fe-Zn mixed powder compacts was investigated in relation to the expansion behavior of the compacts at 259 to 340°C. The ζ phase of a cone shape, which has a non-equilibrium composition ranging from the δ1 to the ζ phase is first formed at the interface between iron and zinc particles, then the conical crystal grows into zinc particles. After the appearance of the Γ and ζ phases the composition of the ζ phase becomes the equilibrium one. Although the compacts expand as long as one of the three phases grows continuously by diffusion of zinc from the zinc particles to the compounds, the growth of the conical ζ phase having a non-equilibrium composition gives rise to the maximum expansion rate. This phenomenon arises mainly from a one-sided diffusion of zinc into the conical crystal.View full abstractDownload PDF (2255K) -
Takashi Yasunaka, Toru Araki1972 Volume 36 Issue 12 Pages 1202-1207
Published: 1972
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe relation between microstructure and tensile fracture for Fe-18Ni-2Al alloy has been studied. In the alloy aged in the temperature range 480 to 550°C, the precipitates were identified by electron diffraction as NiAl or (Fe, Ni)Al of the B2 type structure.
The fracture mode of tensile specimens aged for 3 hr at 480°C, in which intergranular microcracks were initiated before fracture, depended on the prior austenite grain size. In the case of large grain size, the fracture mode was intergranular. On the contrary, specimens with a small grain size was fractured by shearing. The effective intergranular surface energy was estimated as 5.2×105 erg/cm2.
Specimens compressed in the quenched condition exhibited sharp and wavy slip bands and passed through the grain boundary by cross slip. In the aged condition the slip bands became obscure and slip occurred mainly on the {110} plane in the ⟨111⟩ direction even near the grain boundary. This shows that cross slip becomes very difficult and the stress is concentrated at the grain boundary. It is suggested that one of the causes for the brittleness of this alloy is the result of piling-up of dislocations at the grain boundaries due to the difficulty of cross slip and the ease of nucleation and propagation of cracks.View full abstractDownload PDF (2685K) -
Yoshiaki Umehara, Shigeyasu K\={o}da, Sosuke Uchida1972 Volume 36 Issue 12 Pages 1208-1213
Published: 1972
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSA eutectic alloy of InSb-NiSb has been unidirectionally solidified at various rates of solidification in order to investigate the structure change due to solidification condition.
The results obtained are as follows:
(1) The alloy specimens consisted of polycrystalline columnar grains which elongated to the solidification direction. The InSb matrix phase was oriented in the ⟨110⟩ direction to the growth direction. Rods of NiSb were aligned parallel to each other to the growth direction and oriented in the ⟨0001⟩ direction. The size of the rods was 10∼500 μ in length and 0.5∼5 μ in diameter, decreasing with increasing solidification velocity.
(2) The crystallographic orientation relationship between the InSb and NiSb phases was determined by X-ray diffraction. A preferred relationship observed may be roughly stated approximately:
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(3) The spacing between the NiSb rods was expressed to be linear to the rate of solidification R, and λ2R was 1.57×10−10 cm3/sec. Assuming that the crystal growth followed Jackson’s model, the diffusion coefficient obtained was D=3.85×10−8∼5.78×10−8 cm2/sec at the supercooling temperatures between 14° and 21°C.
(4) The relative resistance RB⁄R0 of field plates made of the alloy was measured as a function of the magnetic induction. The resistance increased by a factor of 16 in a field of 10 kG.View full abstractDownload PDF (1763K) -
Mikio Morita, Hiromitu Takeda, Ituo Arima1972 Volume 36 Issue 12 Pages 1213-1217
Published: 1972
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSBoron filaments are tested in tension and the influence of gauge length on their mechanical properties is discussed. The mean fracture stress increases as the specimen’s gauge length becomes shorter due to the decrease in flaw existence probability. The bundle strength which may be used in the “Rule of Mixture” for a composite strength design, is also discussed in relation to the effect of the gauge length of filaments and also to a large variation in filament’s strength even if tested at a fixed length.
Effects of heat treatment in various atmospheres on the fiber’s strength are also studied, and the necessity of protective coating is pointed out.View full abstractDownload PDF (1448K) -
Ishi Miura, Hitoshi Hamanaka1972 Volume 36 Issue 12 Pages 1218-1224
Published: 1972
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSTernary eutectic alloys, Al-CuAl2-NiCu3Al6, Al-CuAl2-FeCu2Al7 and Al-CuAl2-Si, consisting of Al-CuAl2 lamellar eutectics and Al-Al3Ni, Al-Al3Fe or Al-Si fibrous eutectics, were solidified unidirectionally over a wide range of rates. These microstructures are compared with those of concomitant binary eutectics and are discussed with reference to the term of entropy of fusion of each phases. In Al-CuAl2-Si ternary eutectics, Si grows with prefered ⟨100⟩ fiber texture as in Al-Si binary eutectics, though Al-CuAl2 lamellar are degenerated thoroughly. This is considered to come from the difference of entropy of fusion between Si and CuAl2, because the entropy of fusion of Si is higher than that of CuAl2. On the other hand, in Al-CuAl2-NiCu3Al6 ternary eutectics, Al-CuAl2 lamellae are maintained because the difference in the entropy of fusion between NiCu3Al6 and CuAl2 is smaller than that of Si and CuAl2. It may be concluded that with increasing entropy of fusion of the third phase, the influence of Al-CuAl2 on the Al-CuAl2 lamellae becomes greater.View full abstractDownload PDF (3884K) -
Ishi Miura, Hitoshi Hamanaka1972 Volume 36 Issue 12 Pages 1224-1231
Published: 1972
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe present authors have reported on microstructures of unidirectionally solidified Al-CuAl2-Si, Al-CuAl2-NiCu3Al6, Al-CuAl2-FeCu2Al7 ternary eutectic composites in the preceding paper. In the present study, mechanical properties, fracture mechanics and thermal stabilities of these alloys were studied.
Although these ternary eutectic composites are reinforced with two kind of phases, the stress-strain curves consist of two zones, primary and secondary elastic zones, as have been observed in binary eutectic composites. Fracture of the composites occurred by the failure of one of the phases. Therefore, for estimating the tensile strength of the ternary eutectic composites from the law of mixture, we should consider the fracture strain of the two reinforcing phases. Solution treatment and aging of these composites are effective to improve their mechanical properties and fracture behaviour. Thermal stability of the ternary eutectic composites is greatly improved as compared with those of the concomitant binary eutectic composites, because the coarsening of the phases is interrupted mutually the phases.View full abstractDownload PDF (3314K) -
Ishi Miura, Hitoshi Hamanaka1972 Volume 36 Issue 12 Pages 1232-1237
Published: 1972
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSTernary eutectic alloys containing the Al-Si system were unidirectionally solidified, and the effect of the third element or the third phase on the growth morphology of Si in the Al matrix was studied in comparison with those of Al-Si binary eutectic alloys. Growth mechanism of Si is largely influenced by the shape of the solid-liquid interface, which is thought to be effected by the growth habit of the third phase in ternary eutectics. In Al-Si-β(Fe, Si, Al) ternary eutectics, the β phase has a higher entropy of fusion and the solid-liquid interface becomes planar, so the Si phase grows with a platelet or radial section due to the {111} twin. On the other hand, in Al-Si-CuAl2 ternary eutectics, the CuAl2 phase has a lower entropy of fusion, so the solid-liquid interface is uneven and Si grows with a preferred ⟨100⟩ fiber texture as in Al-Si binary eutectics. Although the growth of the Si phase in ternary eutectics seems to be surpressed by the third elements, the effect of them is not clear. It is thought that the third elements in liquid phase have an effect on the growth mechanism of the Si phase in cooperation with the growth of the third phase.View full abstractDownload PDF (3154K) -
Kiyohito Ishida, Taiji Nishizawa1972 Volume 36 Issue 12 Pages 1238-1245
Published: 1972
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSA dilatometric experiment has been made on the fcc\ ightleftarrowshcp martensitic transformation in Fe-Mn-X alloys, and the effects of the alloying elements on the MSγ→ε and ASε→γ temperatures have been studied. It was observed that the ASε→γ temperature was lowered by additions of Al, Co, Cr, Cu, Mo, Nb, Ni, Si, Ti, V, W and C, while the MSγ→ε temperature was lowered by alloying of the above elements except Co. The parameter ΔGXγ⁄εFe which represents the effect of alloying element X on the relative stability of γ-iron and ε-iron near 500°K has been evaluated by thermodynamic analysis of the ASε→γ and MSγ→ε data. It was found that the value of the parameter ΔGXγ⁄εFe changes systematically with the group number in the periodic classification. Another parameter ΔGXα⁄εFe for α-iron and ε-iron was obtained from the values of ΔGXα⁄γFe and ΔGXγ⁄εFe, and the parameter was found to change in accordance with the periodic table.View full abstractDownload PDF (2197K) -
Hiroshi Kubo, Ken-ichi Hirano1972 Volume 36 Issue 12 Pages 1245-1251
Published: 1972
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSGrowth rates of bainite plates in Ag-27.6 wt%Zn and Ag-27.1 wt%Zn alloys have been measured and the activation energies for the growth have been determined.
In Ag-27.6 wt%Zn alloy, the activation energy for the growth of bainite plates in the lower temperature range (185∼225°C) is found to be 17 kcal/mol and different from that in the upper temperature range (above 225°C), 32 kcal/mol. In Ag-27.1 wt%Zn alloy, their growth in the upper temperature range is too fast to be measured, and the activation energy has been determined only in the temperature range of 195∼225°C to be 16 kcal/mol.
In both alloys, the mechanism of the bainitic transformation in the initial stage seems to be different from that in the later stage. In the initial stage the bainite plates are likely to grow by the shear mechanism accompanied with short range inter-diffusion, while in the later stage the transformation seems to proceed with the diffusion of both the species across the non-coherent interphase boundary.
From the values of the activation energy, it is deduced that the longitudinal growth of the bainite plates in the lower temperature range is controlled by the short range diffusion in the matrix, and in the upper temperature range it depends on the short range diffusion in the bainite plate.View full abstractDownload PDF (3074K) -
Shinzo Yano, Shotaro Morozumi1972 Volume 36 Issue 12 Pages 1252-1257
Published: 1972
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSA yield point phenomenon was observed in Al-0.16 wt%Ti alloy when specimens were stretched at room temperature after cold working and annealing under the limited conditions, for example, 1 hr at 280 to 300°C. The phenomenon was most clearly observed in a specimen annealed at 280°C rather than at higher temperatures. Electron microscope observation revealed that the annealed structure of the specimen consisted of very fine subgrains of a few microns, inside of which the dislocation density was low. Therefore, it is concluded that, in addition to locking of dislocations by added titanium, the fine subgrain structure contributes greatly to the phenomenon.View full abstractDownload PDF (2540K) -
Bunkei Ky\={o}, Kumao Uchida, Sh\={o}suke Imoto1972 Volume 36 Issue 12 Pages 1257-1263
Published: 1972
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSStudies were made on the hydrolysis of the titanium mononitride and carbide by superheated steam kept at temperatures from 600 to 950°C. In the case of TiN the reaction products were mainly N2, H2 and the solid residue TiO2. The amount of NH3 was too little to be traced for the change of the reaction. The predominant reaction equation for the hydrolysis of TiN0.81 was found to be:
(This article is not displayable. Please see full text pdf.)
where α covered from 0.02 to 0.08. A small amount of NO gas was also observed. Upon the hydrolysis of TiC, CO, CO2, H2 and a small amount of CH4 were produced and the initiation temperature of the reaction was lower than that for TiN. The amount of CO was the largest at the highest hydrolysis temperature, and CO2 the lowest. The reaction could be given by the equation:
(This article is not displayable. Please see full text pdf.)
where β varied with temperature from 0.04 at 600°C to 0.76 at 950°C. In the hydrolysis at higher temperatures, it was observed that a larger amount of H2 than that expected from the above equation evolved preceding the CO2 evolution. One possible explanation for this might be that some amount of CO produced at the early stage of the hydrolysis was contained within the solid residue and later converted into CO2 by the steam-gas reaction.View full abstractDownload PDF (1538K)
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