ENHANCED SOLID-STATE AMORPHIZATION BY SHARP CONCENTRATION GRADIENTS

The thermodynamic aspects of solid-state amorphization of the Ni-Zr system is reanalyzed considering the effects of concentration gradients. It is shown that during the early stage of the solid-state amorphization the driving force for amorphous-alloy formation will be larger than that for intermetallic-compound formation due to the effects of sharp concentration gradients. This reveals that, in addition to the kinetic constraints, the driving force from sharp concentration gradients also contributes to the solid-state amorphization. The thermodynamic arguments also lead to a three-stage description of the solid-state amorphization, which is in agreement with experimental results.