Influence of Compacting Temperature in Vacuum Hot Pressing on the Microstructure and Mechanical Properties of Al-Ni-Zr Amorphous Alloys Prepared by Mechanical Alloying.

Abstract

Amorphous Al100-xNi0.6xZr0.4x(X=30, 35 and 40) alloys were prepared by double mechanical alloying, and the obtained amorphous alloy powders were consolidated at various compacting temperatures by vacuum hot pressing. Changes of thermal stability, mechanical properties and microstructure of the compacts with the compacting temperature were measured. As a result, amorphous powder double mechanically alloyed begins to crystallize at 670-730K, while the compacts consolidated by the vacuum hot pressing at same temperature range is kept amorphous state. Also both the rupture strength and maximum deflection in the bending for the compacts reach the maximum value when they are consolidated at 750-800 K. In addition, the structure of amorphous phase in the compacts partially begins to crystallize, at the same compacting temperature range, to form ultra fine grains with the composition of Al40Ni51.5Zr8.5 whose average diameter is about 20nm, dispersed through the amorphous matrix.