AMORPHIZATION OF AL-12AT.PERCENT-TI-X (X=CR,FE,NI,CU) MIXED POWDERS BY MECHANICAL ALLOYING

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-(1 0 similar to 15.8)at.%Ti-(3.4 similar to 26.3)at.%X supersaturated sol id solution with small grain sizes of 4 similar to 6 run are obtained. Increase in the concentration of the 3rd element Cr, Fe, Ni, promotes amorphization of the aluminum rich supersaturated solid solution by M A, though no amorphous phase is formed in Al-13.1at.%Ti mechanically a lloyed 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 el astic lattice strain, about 2% due to the largely, reduced lattice par ameter in nano-size crystals is the most important factor for the amor phization of Al-rich supersaturated solid solutions.