AMORPHOUS PHASE GROWTH BY ISOTHERMAL ANNEALING-INDUCED INTERDIFFUSIONREACTIONS IN MECHANICALLY DEFORMED NI TI MULTILAYERED COMPOSITES/

The growth of amorphous phase and the formation of competing intermeta llic compounds in mechanically deformed Ni/Ti multilayered composites have been investigated by X-ray diffraction, scanning electron microsc opy, transmission electron micrography, and magnetic measurement. Expe rimental observations in the Ni/Ti system have been performed, support ing a transient nucleation model for solid-state amorphization. The am orphous layers in the Ni/Ti multilayered composites continue to grow u ntil they have attained a temperature-dependent critical thickness or a temperature-dependent critical annealing time. The relationships bet ween the critical amorphous layer thickness and temperature, between t he critical annealing time and temperature, and between the annealing conditions (temperature, time) and amorphization transformation, have been deduced and compared with the experimental results. The quantitat ive relationships can give a direction for the bulk amorphization in t he Ni/Ti multilayered composites.