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Volume 47, Issue 8
Displaying 1-13 of 13 articles from this issue
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Yasumasa Koyama, Hiroyuki Suzuki, Osamu Nittono1983 Volume 47 Issue 8 Pages 655-662
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe fcc↔fct phase transformation in indium-(6.8, 7.0 at%) mercury alloys has been studied by means of X-ray diffractometry and metallographic technique. The alloys, when cooled from a high temperature corresponding to fcc phase to a temperature above room temperature, undergo a phase separation from fcc to fcc+fct (c⁄a>1). On the other hand, when they are cooled to a temperature below room temperature at a cooling rate more than 0.1 K/s, the fcc→fct martensitic transformation takes place, and surfaces of the fct alloys show a banded relief associated with the martensitic transformation. The shape memory effect is observed in the fct→fcc reverse transformation on heating, and the amount and behavior of shape recovery are strongly influenced by the heating rate. The characteristic features of the phase transformation are well explained by considering the effect of atomic diffusion. The fcc↔fct martensitic transformation is analyzed on the basis of the Landau theory, and some physical quantities such as the second-order elastic constant and change in entropy are calculated and compared with the results of the other indium alloys which undergo the fcc↔fct (c⁄a\gtrless1) martensitic transformation. The stress-strain relation is also obtained. It is shown that the characteristic features of the phase transformation in these indium alloys are explained in terms of their valence electron concentration.View full abstractDownload PDF (1509K) -
Yung-ju Pyun, Teiichi Homma, Kazuo Takakuwa1983 Volume 47 Issue 8 Pages 663-670
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe stress generation behavior in Cu2O grown on Cu has been studied using an X-ray diffraction apparatus, which is provided with a newly designed hot stage unit. The oxidation run has been carried out at temperatures between 573 and 923 K and at oxygen pressures ranging from 25 to 110 Pa for (100) and (111) faces of single crystalline copper discs and surfaces of polycrysalline ones. The stress generation behavior varied depending on temperature and crystalline state of the specimen. At temperatures below the half of the melting point of Cu2O a compressive strain (7×10−3 at 573 K) larger than the fracture strain of the bulk oxide (2×10−3) was observed. This elastic strain diminished at higher temperatures. The oxide scale exhibited a pseudo brittle-ductile transformation between 573-673 K as the bulk oxdie did. A quantitative evaluation of the stress generated in the epitaxial oxide grown on Cu (100) showed values between 1.3 and 3.0±0.5×108 N·m−2, which were 30% larger than the elastic strain generated in the oxide grown on Cu (111). This will result from a new epitaxial effect which is probably due to epitaxial development of a mosaic structure in the oxide but not due to “lattice misfit” at the oxide/metal interface. The strain observed within the elastic range can alter grain to grain due to an elastic anisotropy in the Cu2O crystal. This implies a heterogeneous strain, instead of stress, distribution model to be probable. These observations together with those made by scanning electron microscopy allowed to conclude on the nature of strain generation and also on the athermal effect.View full abstractDownload PDF (1492K) -
Shingo Matsui, Akio Era1983 Volume 47 Issue 8 Pages 671-675
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe extraction equilibrium of aluminum from hydrochloric acid and sulphuric acid solutions was studied by using 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester in DOSB diluent as a function of pH, metal and extractant concentrations. The experimental temperature was 298 K, and the ionic strength of the aqueous solutions was fixed to 3 so as to keep the activity coefficient of the species in the aqueous solutions constant.
In both acid solutions, the extraction mechanism was found to be an ion exchange process, and the extracted species were identified as AlR3·2RH monomer. The apparent equilibrium constants for free aluminum ion were calculated to be 10−1.16 and 10−1.06 for hydrochloric acid and sulphuric acid solutions, respectively.View full abstractDownload PDF (493K) -
Takeshi Kobayashi, Osamu Kujirai, Fumio Hirose, Haruno Okochi1983 Volume 47 Issue 8 Pages 676-682
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSAn analytical method has been established for the determination cf traces of tin in both nickel-base and cobalt-base heat-resisting alloys by graphite furnace atomic absorption spectrometry.
When the alloys were dissolved in a mixture of hydrofluoric acid and nitric acid, the sample solutions were dried, ashed (673 K-30 s) and atomized (2773 K-5 s). Mixed gas of 10% hydrogen and 90% argon was used as a purge gas.
On the other hand, when the alloys were dissolved in a mixture of hydrofluoric acid, nitric acid and orthophosphoric acid (0.2 kmol/m3), the sample solutions were dried, ashed (773 K-30 s) and atomized (2773 K-5 s) by using argon as a purge gas.
Synthetic calibration solutions were prepared by adding tin standard solutions to the cobalt matrix solutions which had the same acid concentrations as those of the sample solutions.
With heat-resisting alloys containing 8-20 ppm of tin, relative standard deviation was within 3% in both dissolution methods. The detection limit for tin was 0.2 ppm in the alloy, when one gram of test portion was used.View full abstractDownload PDF (1745K) -
Hiroshi Maeda, Mitsunori Sato, Mitsuru Uehara1983 Volume 47 Issue 8 Pages 683-687
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSFor Ni2(Mn1−xMx)Sn with M=V and Nb (x=0.1, 0.2, 0.3 and 0.4), and Mn3−y−zCryAlC1+z (y=0 and z=−0.16, −0.08 and 0, and z=0.1 and y=0, 0.06, 0.15 and 0.26) the Curie temperature Tc, the saturation magnetization Ms, and the magnetic entropy ΔSM near Tc have been studied. The values of ΔSM are determined from the measured magnetization-temperature curves. As x or (y+z) increases, the values of Tc linearly decrease from room temperature to about 200 K, and Ms also linearly decreases. The largest values of the maximum magnetic entropy (ΔSM)Max obtained at x=0.1 to 0.2 in the formar system and at y=0 and z=0.1 in the latter one reach about half of that of Gd, and (ΔSM)Max gradually decreases with increasing x or y. Furthermore, the values of ΔSM are calculated using a molecular field approximation. The calculated values are in agreement with the experimental ones for the materials with low x or y, but the difference between the both values becomes large with increasing x or y, and particularly in the formar system with M=Nb and in the latter one with z≤0.View full abstractDownload PDF (645K) -
Hiroshi Maeda, Mitsunori Sato, Mitsuru Uehara1983 Volume 47 Issue 8 Pages 688-691
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESS(Fe1−xNix)90Zr10 (x=0, 0.01, 0.02 and 0.03) and (Fe0.95M0.05)90Zr10 (M=Al, Si, Ga, Ge and Sn) amorphous alloys with thickness of about 20 μm were prepared by a single roll-quenching technique and a piston anvil-quenching one. The Curie temperature Tc, the saturation magnetization Ms and the magnetic entropy ΔSM of the alloys have been investigated. The values of Tc increase from 240 K to near room temperature with increasing x up to 0.05, tending to increase with increasing atomic number of the elements M. The values of ΔSM as well as Ms increase with increasing x, and ΔSM increases in propotion to the magnetic field H. The maximum magnetic entropy (ΔSM)Max of 13 kJ·m−3·K−1 near Tc at H up to 1.12 MA·m−1 is about 50% smaller than that of Gd. However, the change in ΔSM with temperature T is much smaller than those of Gd and other crystallines. The curves of ΔSM-T cannot be approximated by a molecular field theory.View full abstractDownload PDF (530K) -
Noboru Yahata1983 Volume 47 Issue 8 Pages 692-698
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSA comparison of abrasive wear between uni-directional friction and reciprocating friction was made on annealed plain carbon steels sliding aginst fresh Al2O3 abrasive clothes and repeatedly used ones. Wear tests of the two sliding modes were carried out with a testing machine remodeled from a lathe under similar conditions in air. The experiments indicated that in case of fresh abrasive clothes, a heavier wear always resulted from uni-directional friction, and the wear differrences between the two sliding modes increased with increasing normal forces and abrasive garin sizes; in case of repeatedly used ones, a heavier wear resulted from reciprocating friction in steady conditions. The wear differences between the two sliding modes can be explained in terms of the differences in the degree of work-hardening of the rubbed surfaces and the amount of the abrasive grains being blunted, fractured, eroded out of the resin base, clogged and capped with metal chips etc.View full abstractDownload PDF (2090K) -
Kiyoshi Watanabe, Hakaru Masumoto1983 Volume 47 Issue 8 Pages 699-703
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSThe relations between permanent magnetic properties and microstructures of Fe-34-67.5 at%Pt binary alloys were investigated using a recording fluxmeter, X-ray diffraction and electron microscopy. The excellent permanent magnetic properties have been obtained by water-quenching from a temperature in the γ phase range and subsequent reheating at a lower temperature in the γ1 phase range. A typical Fe-38.5 at%Pt alloy exhibits the highest value of maximum energy product of 159 kJ·m−3(20 MG·Oe), with a coercive force of 340 kA·m−1(4.3 kOe) and a residual flux density of 1.08 T(10.8 kG).
It is presumed that the excellent permanent magnetic properties are related to the band microstructure of the γ1 order phase with the L10-type structure and a high crystal magnetic anisotropy.View full abstractDownload PDF (1193K) -
Shotaro Morozumi, K\={o}ichi Suzuki1983 Volume 47 Issue 8 Pages 704-710
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSIn order to investigate the effect of alloying elements on the hydrogen embrittlement of vanadium at moderate temperatures, the metal was alloyed up to about 20 atomic per cent with molybdenum as an endothermic occluder and with titanium as an exothermic occluder, respectively, and then the specimens were hydrogenated up to about 10 atomic per cent of hydrogen. The specimens were tensile tested in the temperature range from room temperature to 573 K. Results obtained were as follows:
(1) Both of molybdenum and titanium increased the solubility limit of hydrogen in vanadium, which was measured by the internal friction method.
(2) The alloying elements deteriorated vanadium for hydrogen embrittlement, by increasing the strength and lowering the ductility.
(3) Therefore, the ductile-brittle transition temperature (DBTT) of hydrogenated alloys, which was determined as a temperature at which just half of the reduction in area of unhydrogenated specimen was obtained in the hydrogenated specimen, was located in the solid solution region as to hydrogen as well as alloying elements at moderate temperatures in phase diagrams.
(4) The brittle fracture mode was different between V-Mo and V-Ti alloys; in the former alloy brittle fracture occurred in the cleavage mode, while the intergranular fracture mode took place in the latter alloy.View full abstractDownload PDF (1515K) -
Shotaro Morozumi, Toshiro Komuro, Seiichi Suzuki1983 Volume 47 Issue 8 Pages 710-716
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSCompacts of molybdenum powder mixed with various amouts less than 2 percent of hydrogenated holmium, lanthanum, mischmetall, scandium and yttrium, respectively, were arc-melted under an argon atmosphere. Button-like ingots were chemically analyzed for carbon, oxygen and added elements in the ingots, tested for the warm workability, and examined by metallography on microstructure and fracture surface.
As it was found that scanduim had an excellent effect on the workability of molybdenum, ingots melted with various amounts of scandium up to 0.5 percent were tested further for the workability and tensile properties at temperatures from 203 to 353 K.
\ oindentResults obtained are as follows:
(1) Among the elements added, scandium had the most distinguished scavenging ability in arc-melting of molybdenum.
(2) The added elements formed their oxides by the reaction with impurity oxygen in the molten molybdenum, and the oxides floated off from the molten metal onto the surface as molten slags.
(3) As a result of deoxidation, the warm workability of molybdenum was improved, on which scandium had the most remarkable effect.
(4) Elements with low deoxidizing ability, e.g. Ho, produced precipitates in the matrix and grain boundaries before they scavenged oxygen enough.
(5) Even though elements, e.g. Sc, had high deoxidizing ability, when they remained in excess in molybdenum, the workability of the metal became lower.
(6) Molybdenum ingots arc-melted with an optimum amount of scandium, say 0.2 percent, had appreciable ductility at about room temperature.View full abstractDownload PDF (2876K) -
Ken-ichi Miyazawa, Takao Choh1983 Volume 47 Issue 8 Pages 717-723
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSMetallic ribbon formation from a cylindrical melt jet in the single-roll rapid solidification process has been investigated to explore the dependence of ribbon geometry on the impinging melt flow on a rotating roll. Results of the experiment using round orifice nozzles and Pb-Sb eutectic alloy show that the spreading of melt on the roll increases with decreasing roll surface velocity and with increasing melt flow rate and melt temperature in nozzle. Effects of the key process parameters on the ribbon geometry are discussed through considering characteristics of the flow.
Furthermore, the impinging flow is dimensionally and approximately analysed to obtain the equation (8) useful for estimating the melt spreading and the ribbon geometry. It has been cofirmed that the boundary layer flow in the melt puddle is laminar and that the melt temperature is about 11% lower in the puddle than in nozzle due to heat transfer to the roll. Effect of the melt surface tension on the ribbon formation can be neglected for Pb-Sb eutectic alloy, but not for Fe- or Cu-based alloys, whose ribbon width is well expressed by Eq. (18).View full abstractDownload PDF (1005K) -
Hideki Hagi1983 Volume 47 Issue 8 Pages 724-725
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSDownload PDF (408K) -
Kazuhiro Nagata, Kazuhiro S. Goto1983 Volume 47 Issue 8 Pages 726-727
Published: 1983
Released on J-STAGE: April 04, 2008
JOURNAL FREE ACCESSDownload PDF (289K)
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