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Volume 42, Issue 5
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Junichi ENDOH, Tadao MUROTA1992 Volume 42 Issue 5 Pages 257-262
Published: May 30, 1992
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSPlastic deformation of an extruded aluminum H-beam was investigated under an unsymmetrical bending condition. The deformation of the cross-section under unsymmetrical bending was characterized through comparison with the deformation under symmetrical bending and pure twisting conditions. An H-beam specimen was set with the web axis inclining by ψ degree from the bending plane (the horizontal plane). Then, bending moment was applied on the H-beam specimen using a cantilever type bending apparatus modified to fit for unsymmetrical bending. Both the transverse bending moment and twisting moment caused by the in-plane unsymmetrical bending were measured. The deformation of the cross-section was also determined. When the web plane coincided with the bending plane (symmetrical bending) the web of an H-beam was not deformed. However, the flange showed sagging deformation. When the web plane was perpendicular to the bending plane, the web was deformed into a shape of a character "C". The flangs was only rotated around the junction between the web and flange. Under unsymmetrical bending, the web was deformed into a shape of a character "S", while the flange deformation was a combination of the sagging and rotation. When the inclination angle ψ was small the sagging deformation of the flange was predominant. On the contrary, the rotation of the flange was predominant when the inclination angle ψ became close to 90°. These results are utilized for preventing the deformation of the cross-section under unsymmetrical bending.View full abstractDownload PDF (908K) -
Tamotsu YAJIMA, Hiroyasu IWAHARA, Norihiko FUKATSU, Teruo OHASHI, Kuni ...1992 Volume 42 Issue 5 Pages 263-267
Published: May 30, 1992
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSIn order to carry out in-situ measurement of hydrogen content in molten aluminum, a galvanic cell type hydrogen sensor was constructed using CaZr0.9In0.1O3-α as a solid electrolyte. This sensor exhibited stable electromotive force (emf) corresponding to hydrogen content (S). A linear relation was found between emf and logarithm of S2. The hydrogen content determined by this sensor was in good agreement with that measured by Telegas method.View full abstractDownload PDF (530K) -
Shuhei OHSAKI, Tsuneo TAKAHASHI1992 Volume 42 Issue 5 Pages 268-273
Published: May 30, 1992
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSLife time to stress corrosion cracking (SCC) of an aluminum alloy A7075-T6 in 3.5%NaCl solution or in pure water was measured under a stress along short transverse direction. SCC process is divided into crack initiation stage and crack propagation stage, and each stage is analyzed by the Weibull's distribution method. In NaCl solution the life time for each stage can be described by a composite Weibull's distribution. The shape parameter of mode 1 in the region with shorter life time is larger than unity, and that of mode 2 in the region with longer life time is close to unity. On the other hand, the life time in pure water follows a single Weibull's distribution with the shape parameter around unity. An average life time is smaller in NaCl solution than in pure water by a factor of 2 to 4. In SCC process of mode 1 in NaCl solution, cracks nucleate at the intergranular corrosion pits.View full abstractDownload PDF (780K) -
Hiroshi ANADA, Yasuhiro YAMAMOTO, Hiroyuki NAKADA, Shizuo TADA1992 Volume 42 Issue 5 Pages 274-280
Published: May 30, 1992
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSAluminum composite pipes reinforced with stainless steel nets were fabricated in the following procedure. A mould core was first prepared by a graphite bar wrapped with both stainless steel nets and aluminum foils. Hollow shaped billets were made using a unidirectional solidification technique after pouring aluminum melt into the mould having the core. Then, the hollow shaped billets were extruded into composite pipes using a mandrel. Aluminum foils used with nets were useful for positioning nets, adjusting spacing between net layers and improving melt filling into billets. The original shape was maintained even after extrusion without failure. The torsional properties of the pipe were improved by adjusting the radial position of nets and by increasing the wrapping number of nets.View full abstractDownload PDF (1393K) -
Nobuo KOBAYASHI, Shu KURODA, Tadakazu OHNISHI, Hiroyuki ICHINOSE1992 Volume 42 Issue 5 Pages 281-286
Published: May 30, 1992
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSStrength and corrosion resistance of an extruded Al-8%Fe P/M alloy has been investigated. Corrosion tests were carried out in a 3.5% NaCl aqueous solution kept at 40°C. Almost no change in the microstructure and strength was observed after heating up to about 400°C, while coarsening of structure and softening occurred above 400°C. The corrosion rate became minimum at a heating temperature of 200°C. The corrosion rate of as-extruded alloy was high in the early stage of corrosion, probably because of the residual stress. Since the residual stress is released by the pitting corrosion, the corrosion rate decreases in the later stage. The high corrosion rate observed after heating at higher temperature is considered to be due to the coarsening of structure and the increase in electrochemical nonuniformity.View full abstractDownload PDF (1015K) -
Hideo NAKAE, KIKYUNG SONG, Hidetoshi FUJII1992 Volume 42 Issue 5 Pages 287-292
Published: May 30, 1992
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSThe change in Si phase morphology at the solid/liquid interface by addition of Sr was observed using an improved unidirectional solidification method to investigate the mechanism of modification of Al-Si alloys. A self sealing method was used to prevent Sr from evaporating and oxidizing. Al-Si alloy was best aligned at a speed of 2mm/h and Sr addition worsened the degree of alignment. As the solidification rate decreased, the degree of interfacial smoothness also decreased in Al-Si-Sr alloy, while it increased in Al-Si alloy. Si phase protruded into the liquid phase in Al-Si-Sr alloy, although Si phase was covered by α phase in Al-Si alloy. That phenomenon was caused by the change in the balance between α phase/liquid interfacial energy and Si phase/liquid interfacial energy. The equilibrium condition was achieved by holding the furnace stationary for 5hours.View full abstractDownload PDF (1404K) -
Preparation of three dimensionally isotropic SiC-aluminum composites and their mechanical propertiesYuji YAMAMOTO, Hajmue IZAWA, Shojiro OCHIAI, Kozo OSAMURA1992 Volume 42 Issue 5 Pages 293-298
Published: May 30, 1992
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSUsing a porous body of silicon carbide which forms a three-dimensional network structure, SiC-aluminum composites were prepared by the liquid phase hot-pressing technique: the porous SiC was infiltrated with molten aluminum under pressure. Each of silicon carbide and aluminum forms a three-dimensional network structure intermingling with each other and the composite shows the following unique properties compared with conventional aluminum matrix composites. The composites are macroscopically isotropic. The compressive strength is 1.2GPa at room temperature and this value is retained up to 473K. Beyond 473K, it decreases gradually with increasing temperature to 0.5GPa at 673K. The bending strength and coefficient of thermal expansion are 480 MPa and 7.5 × 10-6/K, respectively. The Young's modulus is isotropically 230GPa. This value is higher than that of isotropic particle-dispersed aluminum composite, and comparable with that of fiber-reinforced aluminum composite in longitudinal direction but higher than that in transverse direction.View full abstractDownload PDF (1159K) -
Akihisa INOUE, Tsuyoshi MASUMOTO1992 Volume 42 Issue 5 Pages 299-305
Published: May 30, 1992
Released on J-STAGE: October 30, 2008
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Toshiya SHIBAYANAGI, Shigenori HORI1992 Volume 42 Issue 5 Pages 306-315
Published: May 30, 1992
Released on J-STAGE: October 30, 2008
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Katsuaki SUGANUMA1992 Volume 42 Issue 5 Pages 316-318
Published: May 30, 1992
Released on J-STAGE: October 30, 2008
JOURNAL FREE ACCESSDownload PDF (313K)
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