THE EFFECT OF SIMPLE METAL (AL, GA) ADDITION ON THE CRYSTALLIZATION AND DENSITY OF AMORPHOUS ZR-NI ALLOYS

Amorphous metal ribbons of (Zr0.64Ni0.36) 1-xMx where M=Al, Ga and (Zr0.5Ni 0.5)1-xAlx for values of x between 0 and 0.25 have been prepared by a rapid quenching technique of melt spinning. The effect of adding Al or Ga to Zr0.64Ni0.36 and Zr 0.5Ni0.5 is to increase the crystallisation temperature of both host alloys. The effect of Al or Ga substitution on the thermal stability of (Zr0.64Ni0.36)1-xMx is very similar. At a composition between x=0.05 and 0.10, the M component completely suppresses the transformation to intermediate phases that has been observed in the crystallisation process for amorphous Zr-Ni alloys in a small composition range near 64 at.% Zr. The density of (Zr0.64Ni0.36) 1-xAlx and of (Zr0.5Ni0.5) 1-xAlx decreases linearly while that of (Zr 0.64Ni0.36)1-xGax remains almost constant with x. An extension to ternary and higher order alloys of the Buschow kinetic model predicting the crystallisation temperature of binary alloys is proposed.