Formation of amorphous Ti-50at.%Pt by solid state reactions during mechanical alloying

Abstract

Mechanical alloying of an equiatomic mixture of crystalline elemental powders of Ti and Pt in a high-energy ball mill results in formation of an amorphous alloy by solid-state reactions. Mechanical alloying was carried out in an argon atmosphere at a rotation speed of 1200 r/min and a 20:1 ball-powder weight ratio for time intervals ranging from 4 to 40 hours. At an intermediate stage of mechanical alloying, scanning electron microscopy showed the formation of characteristic layered structures of inhomogeneous composition within the powder particles. X-ray diffraction analysis showed the gradual disappearance of crystalline Bragg peaks and at the same time the emergence of broad amorphous maxima as milling progressed. The amorphization process was completed after 8-12 hours. The amorphous state of the product indicated that temperatures during processing do not exceeded the crystallization temperature of the alloy.