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Volume 55, Issue 3
Displaying 1-7 of 7 articles from this issue
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RESEARCH REPORT
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Katsushi MATSUMOTO, Yasuaki SUGIZAKI2005 Volume 55 Issue 3 Pages 113-119
Published: 2005
Released on J-STAGE: February 24, 2006
JOURNAL FREE ACCESSEffects of initial microstructure and cold rolling reduction on texture evolution in an Al-Mg-Si alloy were investigated, focusing on formation of Cube and Goss orientation components. Hot gauge samples were annealed at several conditions, and cold rolled to reductions ranging from 40 to 80%, and solution heat treatment (SHT) was finally performed. Cube component, which drastically decreased with increasing cold rolling reduction, however, remained in the deformed matrix as a result of forming so-called cube bands. Development of Cube component after SHT was considered to be governed by three-dimensional distribution of Cube bands, deformation texture developments corresponding to favorable growth conditions of cube grains, and solid solubility of Mg and Si into matrix, which varied with intermediate annealing conditions of hot gauge samples and cold rolling reduction. On the other hand, it was suggested that Goss component after SHT was mainly due to starting microstructure such as deformed or recrystallized microstructure, especially evolution of Brass or S component.View full abstractDownload PDF (5090K) -
Tomo-o TANAKA, Masaya ITO, Toshio NARITA2005 Volume 55 Issue 3 Pages 120-124
Published: 2005
Released on J-STAGE: February 24, 2006
JOURNAL FREE ACCESSIn the joining of aluminum alloy/silicon nitride ceramic, the possibility of the application as a brazing filler metal of the Al-27.1%Cu-4.7%Si ternary eutectic alloy was examined. In the joining at the 833 K in the nitrogen atmosphere, the joining strength were obtained about 65 MPa, and it was clarified that the joining of ceramic and aluminum alloy was possible. Because of the relationship between the joining strength and the existence ratio of Al2Cu at the joining interface, it was considered that Mg, which was included in aluminum alloy, caused the decomposition of aluminum alloy oxidation scale and promoted the diffusion of Cu, and reduced the deposition of Al2Cu.View full abstractDownload PDF (1110K) -
Haruhiko ABE, Shin-ya KOMATSU, Masato HAMAOKA, Masahiko IKEDA, Takeo S ...2005 Volume 55 Issue 3 Pages 125-130
Published: 2005
Released on J-STAGE: February 24, 2006
JOURNAL FREE ACCESSTo study the bake-hardening behavior of Cu added Al-1%Mg2Si alloys by the tensile test after resistivity measurement, resistivity of many samples taken from a rolled sheet was measured in various stages of heat treatment. The resistivity ρSTQ in the 848 K-3.6 ks solution treated and water quenched state (STQ) fluctuated within ranges of 0.9 to 1.7 nΩm. There were good linear relations between the ρSTQ and resistivity after room temperature pre-aging for 1 day (ρRTP) for each of four alloys. The ρRTP values were maintained after short period final aging at 448 K. Possible causes of the fluctuation in ρ were checked. Effects of the STQ conditions on the ρSTQ were negligible. Because the Matthiessen plot of the ρRTP gave good straight lines having acceptable gradient, the fluctuation is not due to errors in size factor and resistance. Change in room temperature showed no correlation with increment up to the ρRTP. Therefore, it is concluded that the ρSTQ of rolled plates used in a series of study have a stripe shaped distribution of the ρSTQ ranging ±0.25 to 0.5 nΩm in the transverse direction with width of 10 to 20 mm extending about 360 mm in the longitudinal direction. In a rough estimation, this fluctuation in ρ is corresponding to variation in Mg, Si or Cu contents of ±0.05 to 0.15 mass% from analysed compositions, though the species of alloying elements is not clear.View full abstractDownload PDF (794K) -
Jyh-Tyng CHOU, Hironori SHIMAUCHI, Ken-ichi IKEDA, Fuyuki YOSHIDA, Hid ...2005 Volume 55 Issue 3 Pages 131-136
Published: 2005
Released on J-STAGE: February 24, 2006
JOURNAL FREE ACCESSIn order to establish a preparation method of pure magnesium samples for OM and SEM/EBSP method, the surfaces of magnesium polycrystal were chemically polished by various solutions. For OM observation and twin observation for SEM/EBSP method, the optimum etching condition was chemical polishing with 20% hydrochloric acid ethanol and 5% nitric acid ethanol. For SEM/EBSP analysis, the optimum etching condition was chemical polishing with a mixture of, nitric acid, hydrochloric acid and dehydrated ethanol of 1 : 2 : 7 in volume ratio. Furthermore, in this study, the crystal orientations of pure magnesium polycrystal treated with above solution were analyzed by SEM/EBSP method. It was found that there are many twins in the samples and all the twins are (1012) type twin. In addition, it was clarified that the orientation relationships between a twin and a neighbor grain and between twins have specific features. When the tip of twin was on boundary, the misorientation of twin and neighbor grain was about 40 degree. When a twin pierced through a grain boundary, the misorientation between twin and neighbor grain was about 75 degree. When twins were crossed each other and the tip of twin touched the other twin, the misorientation of twins was about 60 degree.View full abstractDownload PDF (10712K) -
Yuichi ASANO, Junichi KANEKO, Makoto SUGAMATA, Masahiro KUBOTA2005 Volume 55 Issue 3 Pages 137-141
Published: 2005
Released on J-STAGE: February 24, 2006
JOURNAL FREE ACCESSWith a purpose of obtaining materials showing high specific tensile strength, Mg-5mass%Ca-Al-Zn quaternary alloys of varied Al and Zn compositions were rapidly solidified and subsequently consolidated to the P/M (powder metallurgy) materials by cold-pressing and hot-extrusion. In the tested alloys, Al and Zn contents were varied while Al+Zn content was kept to 12mass%. The results of X-ray diffraction revealed that formation of Ca2Mg6Zn3 ternary compound increased while that of Al2Ca decreased with an increase of Zn/Al content ratio. In as-extruded P/M materials, fine Ca2Mg6Zn3 and Al2Ca compound particles of 100 to 200 nm in size were dispersed uniformly in the Mg matrix. The P/M materials of all tested alloys showed high tensile strength above 450 MPa and density not higher than 1.9 Mg/m3. Moreover, tensile strength increased with increasing Zn/Al ratio and Mg-5Ca-10Zn-2Al alloy showed the highest tensile strength of 600 MPa at RT and 311 MPa at 473 K. In Mg-Ca-Al-Zn alloys, thus, formation of Ca2Mg6Zn3 is more effective in increasing strength than that of Al2Ca since volume fraction of Ca2Mg6Zn3 is higher than that of Al2Ca for the same Ca content.View full abstractDownload PDF (1004K) -
Harushige TSUBAKINO, Yuichiro YAMAMOTO, Atsushi YAMAMOTO, Michitaka TE ...2005 Volume 55 Issue 3 Pages 142-146
Published: 2005
Released on J-STAGE: February 24, 2006
JOURNAL FREE ACCESSSurface segregation phenomena of several transition elements (Fe, Ni, Mn, Co, Cr) in high purity aluminum foils annealed at various temperatures were studied by Rutherford back scattering spectroscopy (RBS) and transmission electron microscopy (TEM). These all elements segregated at the foil surface and detail segregation position was the interface between aluminum oxide and matrix. The degree of surface segregation (α=surface segregation composition/foil composition) depended on the element, annealing temperature and initial foil composition. The empirical rule for the surface segregation was obtained in this study as follows: the maximum α of each element was roughly dependent on the inverse of solid solubility of each element in aluminum.View full abstractDownload PDF (2223K)
OYAMADA MEMORIAL LECTURE
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Fumiaki FUKUCHI, Noboru HAYASHI, Tsutomu OGAWA, Osamu YOKOYAMA, Izuru ...2005 Volume 55 Issue 3 Pages 147-152
Published: 2005
Released on J-STAGE: February 24, 2006
JOURNAL FREE ACCESSDownload PDF (3022K)
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