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Volume 48, Issue 10
Displaying 1-8 of 8 articles from this issue
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RESEARCH REPORT
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Makoto INOUE, Michinori OHKUBO, Makoto SUGAMATA, Junichi KANEKO, Jiro ...1998 Volume 48 Issue 10 Pages 479-483
Published: 1998
Released on J-STAGE: March 30, 2007
JOURNAL FREE ACCESSCreep and creep rupture tests were carried out for MIG welded joints of 5083 aluminum alloy plates under an ambient atmosphere at temperatures between 573 and 723 K. Obtained results were compared to those for the base metal. 5083-O plates of 20 mm thickness were welded by high current MIG welding using 5183 filler wire with a single welding pass for each side. Round bar creep specimens were machined out of the welded joints. The welded joints showed nearly the same minimum creep rate as the base metal at 573 K. However, the minimum creep rate of the welded joints was generally lower than that of the base metal at 623 and 673 K. At these temperatures, creep rupture of the welded specimens always occurred in the base metal. In the welded specimens, creep strain is not uniform and the base metal tended to creep preferentially to the weld metal. The Larson-Miller plot of the rupture time of the welded joints coincided with that of the base metal. High temperature tensile strength of welded joints is slightly higher than that of the base metal.View full abstractDownload PDF (1197K) -
Shin-ya KOMATSU, Masahiko IKEDA, Kaneaki OGAWA1998 Volume 48 Issue 10 Pages 484-488
Published: 1998
Released on J-STAGE: March 30, 2007
JOURNAL FREE ACCESSA positive deviation from the Matthiessen's Rule (DMR) of solute Zn in Mg was previously predicted. To confirm and to quantitate the above prediction, Mg–Zn alloys containing up to 10%Zn were prepared and, after long period solution treatment, dependences of resistivity on Zn concentration and on temperature of resistivity measurement were investigated. The completion in dissolution of eutectic precipitates was confirmed by optical micrography, X-ray diffractometry and saturation of decrease in resistance ratio by isothermal solution treatment. Resistivity of perfect solid solutions up to 6.70 mass (2.60 at)%Zn shows a good linear relationship to f(X) =X(1−6.16X), where X is atomic fraction of solute Zn obtained by chemical analysis of the resistivity specimen, as
43.8<ρD300/nΩm=[1075.8X(1−6.16X)+43.8]±0.4<67.0
5.2<ρD77/nΩm=[992.4X(1−6.16X)+5.22]±0.1<26.6.
These relations, which should be called as corrected Nordheim's Rule, give contribution per unit concentration of solute Zn to resistivity, ΔρZn/nΩm (at%)−1, as 10.76 at 300 K and as 9.92 at 77 K. dρ/dTmeasured between 280 and 305 K increases with X, also corresponding to the positive DMR of solute Zn in Mg. Ratio of these ΔρZn at 300 K and 77 K, η=Δρ300/Δρ77, is 1.088. However, next relation employing η= 1.093 gives the smallest intercept of regression line and is recommended as DMR corrected empirical relation,
5.2<ρD77/nΩm=[37.98/(R−1.093)]±0.1<26.6.
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Hiroyuki TANIHATA, Tomoyuki SUGAWARA, Kenji MATSUDA, Susumu IKENO1998 Volume 48 Issue 10 Pages 489-493
Published: 1998
Released on J-STAGE: March 30, 2007
JOURNAL FREE ACCESSThe effect of homogenizing treatment on the type of Al–Fe–Si intermetallic compound phases in 6063 aluminum alloys was investigated using X-ray diffraction and transmission electron microscopy (TEM). The four kinds of alloys containing 0.1 to 0.5 mass%Fe were melted and then cooled at three cooling rates ranging from 0.06 to 50 K/s, followed by the homogenization at 858 K for 54 ks and 2.4 Ms. The Al–Fe–Si compound particles were extracted from the alloy ingots using the thermal phenol method. A large amount of the β phases (monoclinic: a=b=0.612 nm, c=4.15 nm, β=91°) were found in the ingot containing 0.1 mass%Fe obtained by casting cooling rate of 0.06 K/s. When that ingot was homogenized at 858 K for 54 ks and 2.4 Ms, the amount of the β phases had a tendency to decrease, and that of the α' phases (hexagonal: a=1.23 nm, c=2.62 nm) had a tendency to increase. Moreover, a large amount of the α phases (cubic: a= 1.252 nm or 1.256 nm) were found in the ingot containing 0.5 mass%Fe obtained by casting cooling rate of 50 K/s. When that ingot was homogenized at 858 K for 54 ks, a large amount of the α phases remained like the as-cast ingot. However, in that ingot homogenized at 858 K for 2.4 Ms, the main Al–Fe–Si compound particles changed from the α phase to the α' phase. In the 0.2 mass%Fe ingot at the casting cooling rate of 5 K/s, as solidified condition of commercial alloys, the β phase gradually decreased and the relative frequency of the α phase increased from 10% to 40% in homogenizing at 858 K for 54 ks. However, that of the α' phase also increased to 50% in homogenized ingot. Furthermore, in that ingot homogenized at 858 K for 2.4 Ms, almost all the Al–Fe–Si compound particles were the α' phase.View full abstractDownload PDF (1193K) -
Hisamichi KIMURA, Akihisa INOUE, Kenichiro SASAMORI, Kazuhiko KITA, Te ...1998 Volume 48 Issue 10 Pages 494-500
Published: 1998
Released on J-STAGE: March 30, 2007
JOURNAL FREE ACCESSPowder metallurgy (P/M) alloys of AFCT (Al–6.3%Fe–3.8%Cr–3.3%Ti)–26P/M, AFCT–125P/M, ACFT (Al–5.5%Cr–4.1%Fe–3.3%Ti)–26P/M, ACFT–125P/M, AFCV (Al–6.3%Fe–3.6%Cr–3.6%V)–75P/M, AFMT (Al–6.0%Fe–3.8%Mn–3.2%Ti)–26P/M and AFMT–125P/M were prepared by extruding at 673 K gas atomized powders with sizes smaller than 26 μm, 75 μm and 125 μm, respectively. The constituent phases were Q.C. (quasicrystalline)+Al+Al23Ti9 +Al13Fe4 for the ACFT–P/M alloy, Q.C.+Al for the AFCV–75P/V, Q.C.+Al+Al23Ti9+Al13Fe4+Al6Mn for the AFMT–P/M alloy. The ultimate tensile strength (σUTS), 0.2% proof strength (σ0.2), plastic elongation (εP), Young's modulus (E) and Vickers hardness (HV) of the P/M alloys are in the range of 495 to 650 MPa, 370 to 550 MPa, 3.3 to 7.3%, 80 to 91 GPa and 150 to 192, respectively, at room temperature. The σUTS and σ0.2 of the AFCT–26P/M and ACFT–26P/M alloys were higher than 300 MPa even after heating for 100 h at 573 K. The quasicrystalline particles in the P/M alloys have an icosahedral structure and their particle size is 200 to 900 nm. In the ACFT–26P/M alloy with high elevated-temperature strength, the particle size and morphology of the icosahedral phase remained unchanged even after heat-treatment for 300 h at 573 K. The specific wear rate of the AFCT–26P/M alloy is as smaller as 2.7 × 10−7 mm2/kg at the sliding velocity of 0.5 m/s and 2.8 × 10−7 mm2/kg at 2.0 m/s and almost independent of sliding velocity.View full abstractDownload PDF (1413K) -
Yoshihiro NAKAYAMA, Kenichi SUGAWARA, Nobuaki OHNISHI1998 Volume 48 Issue 10 Pages 501-506
Published: 1998
Released on J-STAGE: March 30, 2007
JOURNAL FREE ACCESSBoth solution and age treatment condition were systematically investigated in order to obtain prominent toughness of Al–4%Si–0.4%Mg casting alloy. Relation between microstructure and mechanical properties was studied from the viewpoints of morphology and size of eutectic Si particle and concentration of solute atoms. The excellent elongation to fracture and absorbed energy in the impact fracture were measured for the specimen solution treated at 838 K for 3 h. The elongation to fracture and absorbed energy of Al–4%Si–0.4%Mg alloy solution treated at 838 K for 3 h and subsequently aged at 418 K, showed about 75% and 180% increase in comparison with those of AC4CH alloy, respectively.View full abstractDownload PDF (1357K) -
Fumie SEKI, Taichi KAMIJO1998 Volume 48 Issue 10 Pages 507-510
Published: 1998
Released on J-STAGE: March 30, 2007
JOURNAL FREE ACCESSThe recrystallization texture in high purity aluminum foils for electrolytic condenser varies extensively with the conditions of cold rolling and heat treatment. The formation behavior of cube texture has been found to depend distinctly on the iron content less than 0.01 mass%, using hot rolled plates containing 7 ppm (4N) and 35 ppm Fe (3N). It has been elucidated that sharp cube texture can be developed in the 4N foils easily by high reduction cold rolling and high temperature final annealing, the combined process of an intermediate annealing at 260°C and a low reduction rolling prior to final annealing is indispensable to develop the cube texture and use of small diameter rolls in the final stage of rolling is effective to suppress the R component in the 3N foils, and the intermediate annealing temperature at 260°C is too high for the 4N foils.View full abstractDownload PDF (578K) -
Hidenori FUJII, Makoto SUGAMATA, Junichi KANEKO1998 Volume 48 Issue 10 Pages 511-516
Published: 1998
Released on J-STAGE: March 30, 2007
JOURNAL FREE ACCESSRapidly solidified P/M materials were prepared for Al–Mg–Si ternary alloys of nine different compositions with higher alloying additions than the commercial Al–Mg–Si alloys. The rapid solidification was performed by argon gas atomization and subsequent splat quenching on a water-cooled copper roll. The rapidly solidified flakes were consolidated to P/M materials by cold pressing, vacuum degassing and hot extrusion at 673 K with a reduction of 25:1. Cast ingots of these alloys were also hot-extruded under the same conditions to the I/M reference materials. For all the tested alloys, tensile strength of the as-extruded P/M materials is higher than that of the I/M counterparts. The tested alloys were grouped into two classes according to the changes in hardness and tensile strength of the P/M materials with increasing Mg+Si content. The alloys containing excess Mg to the Mg2Si composition showed higher hardness and tensile strength than those without excess Mg at the same Mg+Si content. It is considered that both Mg solid solution and dispersion of Mg2Si particles were contributing to the strength increases in the P/M materials. The mechanical properties at room temperature were highest for the P/M material of Al–13%Mg–4%Si alloy which showed tensile strength of 516 MPa, specific modulus of 44.7 GPa/g/cm3 and specific strength of 204 MPa/g/cm3.View full abstractDownload PDF (1292K)
REVIEW
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Koichi TADA1998 Volume 48 Issue 10 Pages 517-524
Published: 1998
Released on J-STAGE: March 30, 2007
JOURNAL FREE ACCESSDownload PDF (1477K)
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