|Budget Amount *help
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1997: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1996: ¥1,600,000 (Direct Cost: ¥1,600,000)
During mechanical alloying, MA,using a high energy planetary ball mill of Al-12at%Ti-X (X=Cr, Fe, Ni, Cu) mixed powders, aluminum rich Al- (10-15.8) at%Ti- (3.4-26.3) at%X supersaturated solid solution with small grain sizes of 4-6nm are obtained. Increase in the concentration of the 3rd element Cr, Fe, Ni, promotes amorphization of the aluminum rich supersaturated solid solution by MA,though no amorphous phase is formed in Al-13.lat%Ti mechanically alloyed powder. On the other hand, dissolution of about 12at%Cu in Al-11at%Ti supersaturated solid solution causes no amorphization during MA.The results obtained suggest that a critical value of the total elastic lattice strain, about 2%, due to the largely reduced lattice parameter in nano size crystals is the most important factor for the amorphization of Al-rich supersaturated solid solutions.
The powder of supersaturated solid solution of Al-7.8at%Ti-0.3at%Fe with a nanocrystalline, prepared by MA,was compacted to columnar shape material at low temperature by application of high pressure of 3GPa. Diffusion of copper was studied in this compacted nanocrystalline material using and ion mass microanalyzer. The interfacial diffusion coefficient of copper in the nanocrystalline materials is fairly higher than the volume diffusion coefficient of copper in aluminum, and the activation energy of the interfacial dirrusion is quite small when compared with that of volume diffusion of copper in aluminum.