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Volume 75, Issue 9
Displaying 1-8 of 8 articles from this issue
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Regular Articles
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Atsuhiro Miyata, Akio Nishimoto, Katsuya AkamatsuArticle type: Regular Article
2011 Volume 75 Issue 9 Pages 469-473
Published: 2011
Released on J-STAGE: September 01, 2011
JOURNAL FREE ACCESSCr-Si intermetallic compound coatings were coated on an austenitic stainless steel SUS310S substrate by pulsed electric current sintering process to improve its wear and oxidation resistances. The coating was carried out for 0.6-10.8 ks at 1073-1323 K at a coating pressure of 60 MPa. As a result of pin-on-disk wear test, the wear property of the coatings was more excellent than that of the substrate. The tensile strength of the coatings was 10-20 MPa. These coatings fractured at the interface between the coatings and the substrate during tensile test. As a result of hot hardness test, the coatings showed higher hardness than the substrate, even at high temperature. Hardness of the coatings fell gradually up to the transition temperature of 870 K and decreased rapidly on further heating. As a result of oxidation-testing for 700 ks at 1123 K, the mass increase of the coatings after oxidizing was less than that of the substrate. These results indicate that wear resistance and strength at elevated temperature could be given to the substrate without deteriorating oxidation resistance.
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Kazutaka Fujita, Kousuke Misumi, Wei Zhang, Akihisa InoueArticle type: Regular Article
2011 Volume 75 Issue 9 Pages 474-478
Published: 2011
Released on J-STAGE: September 01, 2011
JOURNAL FREE ACCESSFatigue test was carried out on Ni-based bulk metallic glass (BMG) for which there is still no reports on fatigue strength. Test alloy rods with a diameter of 2 mm were prepared in Ni60Zr20Nb15Al5 at% systems by copper mold casting method. The tensile strength (σB) was 2.9 GPa. The test specimens were machined to hourglass shape type with a minimum diameter of 0.9 mm. The specimens were tested at a stress ratio of 0.1 and a frequency of 10 Hz. The fatigue limit (σW) and fatigue ratio (σW/σB) in the Ni-based BMG showed high values of 1.68 GPa and 0.58, respectively. The tendency that the σW increased with increasing the σB in BMGs was indicated in the Ni-based BMG. In addition, the fatigue fracture toughness in the Ni-based BMG showed a high value of 14 MPa•m1/2.
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Shigeru Saito, Toshiyuki Takashima, Katsumi Miyama, Kazuya Kurokawa, T ...Article type: Regular Article
2011 Volume 75 Issue 9 Pages 479-484
Published: 2011
Released on J-STAGE: September 01, 2011
JOURNAL FREE ACCESSCompositions with tie-lines between the γ and δ phases in a binary Re-Ni system were investigated at 1423, 1573, and 1773 K by heat-treating of Ar-arc-melted Re-40 at%Ni alloy. The microstructures of the Re-40 at%Ni alloy which had been water-quenched after various heating times were observed and their concentration profiles for Re and Ni were measured using an electron probe micro-analyzer (EPMA). The Re-40 at%Ni alloy consisted of the γ and δ phases.
The tie-lined compositions of the γ and δ phases are summarized as follows (in at%); γ: 13.4Re-86.6Ni, δ: 71.7Re-28.3Ni at 1423 K, γ: 16.4Re-83.6Ni, δ: 69.3Re-30.7Ni at 1573 K, γ: 20.2Re-79.8Ni, δ: 65.3Re-34.7Ni at 1773 K.
The Re-Ni alloy powder sintered using the Spark Plasma Sintering (SPS) method were investigated. Solubility limit of Ni in the δ phase in the binary alloy system at 1423 K was found to be 28.3 at%Ni.
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Takeshi Omura, Yasuyuki HayakawaArticle type: Regular Article
2011 Volume 75 Issue 9 Pages 485-492
Published: 2011
Released on J-STAGE: September 01, 2011
JOURNAL FREE ACCESSA grain-oriented electrical steel has a significantly low iron loss by selective growth of grains with {110} 〈001〉 orientation called as Goss orientation. The selective growth of Goss grains is generally attained by making use of a phenomenon termed ‘secondary recrystallization’. We have already investigated primary recrystallized grains encroached easily by Goss grain and discussed influence of primary-recrystallization texture on the selective growth of Goss grains roughly.
This paper investigates normal growth behavior of primary recrystallized grains in the middle of secondary-recrystallization annealing and discusses influence of primary-recrystallization texture on the selective growth of Goss grains in detail. In this study, several grain-oriented electrical steel samples were prepared by controlling the heating pattern in secondary-recrystallization annealing. The primary-recrystallization texture and primary recrystallized grain size were measured in samples before secondary-recrystallization annealing and in the middle of secondary-recrystallization annealing.
The results are as follows. (1) In secondary-recrystallization annealing, the normal grain growth of primary recrystallized grains having misorientation angle between 25-40 degree to Goss orientation was high. (2) It was considered that the normal grain growth in the middle of secondary-recrystallization annealing had a large influence on selective growth of Goss grain. (3) The change of primary-recrystallization texture in the middle of secondary between heating patterns was caused by the change of the normal grain growth.
Next, we predicted crystal orientation after the secondary recrystallization by the analysis of primary-recrystallization texture in the middle of secondary-recrystallization annealing. In the prediction, the frequency and the mobility dependence on misorientation angle are taken into account.
The expected result showed good agreement with the experimental result. This result was the same as the reported result before. Additionally, it was considered that the nucleation frequency of Goss grain in the primary-recrystallization texture had influence on this expectation.
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Akihiro Yoshimura, Ichiro Daigo, Yasunari MatsunoArticle type: Regular Article
2011 Volume 75 Issue 9 Pages 493-501
Published: 2011
Released on J-STAGE: September 01, 2011
JOURNAL FREE ACCESSRecently, recycling of rare metals has been of great interest because of the rapid growth in their demands and maldistribution of the natural resources. Substance flow analysis (SFA) is a useful tool to figure out the flow of substance in specific regions. However, few SFA has so far been conducted for rare metals. In this paper, we focused on indium and conducted SFA of indium in Japan and global scale. The most of indium is used as Indium Tin Oxide (ITO). The end use of ITO was categorized into 2 groups; Liquid Crystal Display modules and Plasma Display Panel modules, which were further assembled to final end-use products. Quantified was the flow of indium during its lifecycle; mining and smelting, manufacturing, use and waste management. In mining and smelting, the data about the indium content in ore and production of primary metal of indium during 1999-2008 were collected. In manufacturing, we estimated the content of indium of final end-use products, and estimated the input of indium for producing ITO in Japan. Then, we extrapolated the results to SFA in global scale. In-use stock and discard of indium were estimated by dynamic SFA, in which the time-series data about the input of indium in final end-use products and their lifetime distribution were used. In this study, we estimated the loss of indium in each process as recovery potential. It was found that the extraction rate of indium in mining and smelting process was 8-11%, and the loss of indium in the process was 4,826 t in 2004. The amount of loss in manufacturing process was 310 t, in-use stock of indium was 115 t, and the discarded indium in end-of-life products was 5 t in global scale in 2004. Therefore, it was concluded the biggest recovery potential of indium was in mining and smelting.
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Keijiro Nakasa, Masahiko Kato, Takashi Kubo, Akihiro YamamotoArticle type: Regular Article
2011 Volume 75 Issue 9 Pages 502-508
Published: 2011
Released on J-STAGE: September 01, 2011
JOURNAL FREE ACCESSArgon ion sputter etching was applied to three kinds of tool steels at a radio frequency power of 50 W to 250 W for 0.5 ks to 16.2 ks. Pillar-shaped protrusions with diameters or widths of 100 nm to 1 μm were formed on the surface of SKH51 and SKD5 steel plates, and conical protrusions of similar size were formed on the surface of the SKD61 steel plate. The size of both types of protrusions was typically comparable to the wavelength range of visible light, i.e. 400 nm to 800 nm. The absolute reflectance of the SKH51 steel surface was about 0.3% with a sputter power of 200 W and a sputter etching time of 10.8 ks. The reflectance is nearly constant and is independent of the 400 nm to 800 nm wavelength and incident angle of less than 60°. This indicates that sputter etching of tool steels can produce satisfactory anti-reflection bodies with excellent mechanical properties.
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K. Nomura, Y. Miwa, Y. Takagawa, C. Watanabe, R. Monzen, D. Terada, N. ...Article type: Regular Article
2011 Volume 75 Issue 9 Pages 509-515
Published: 2011
Released on J-STAGE: September 01, 2011
JOURNAL FREE ACCESSThe enhancement of strength of a Cu-1.4 mass%Ni-0.25 mass%P-0.1 mass%Zr alloy, in which the Ni and P contents are about twice larger than those in commercial Cu-Ni-P alloys, has been tried by means of combining accumulative roll-bonding (ARB) process by 7 cycles and aging treatment at 350 to 450°C. For the sake of comparison, the mechanical properties of the alloy conventionally cold-rolled to a reduction of 50% and 90% and aged at 350 to 450°C have also been examined. The grain sizes of the Cu-Ni-P-Zr specimens deformed by 7-cycle ARB process and 90% cold-rolling were refined down to about 0.4 μm and 4 μm, respectively, and the fractions of high angle grain-boundaries in the specimens were nearly the same, about 45%. Initial aging, subsequent ARB process or 90% cold-rolling and re-aging at 400°C produced the Cu-Ni-P-Zr alloy highly strengthened. The alloy, initially aged, then ARB-processed and re-aged, had a tensile strength of 780 MPa, an elongation of 6% up to failure and an electrical conductivity of 56% IACS. The differences in yield strength among the re-aged specimens after 50% and 90% cold-rolling and ARB process are explained by the differences among the dislocation density, grain size and inter-precipitate spacing.
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Naoki Matsui, Naoyuki Sano, Junsuke Fujiwara, Keiichiro Ohishi, Tadaka ...Article type: Regular Article
2011 Volume 75 Issue 9 Pages 516-523
Published: 2011
Released on J-STAGE: September 01, 2011
JOURNAL FREE ACCESSMicrostructures and element distribution at the interface between a worn tool surface and a residue of low carbon cutting steel, which was left behind and accumulated on the tool surface during its machining, were observed and analyzed by transmission electron microscopy (TEM) and laser-assisted three dimensional atom-probe tomography (LA3DAP). The residue of the machined steel was composed of fine ferrite grains a few hundred nanometers in size, which were considered to be a result of a grain refinement process by severe plastic deformation. Tungsten carbide (WC) particles embedded in the tool were sharply worn out at the interface, thus the interface was found to be flat and sharp in nanometers scale. Since the deposited steel on the worn tool surface was so tightly bound that the interface was successfully analyzed by LA3DAP in transverse direction. It was shown that tungsten atoms from the WC particles had diffused into the deposited steel with a distance of approximately 10 nm from the interface. It has been suggested that the tool wear upon machining low carbon cutting steels proceeds mainly by the diffusion of tool component elements into the deposited iron, in which accelerated diffusion occurs due to the fast diffusion paths created by severe plastic strains introduced during machining.
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