Formation of amorphous Ti-50 at.% Pt by solid-state reactions during mechanical alloying
ML Mahlatji, S Chikosha, HK Chikwanda, WE Stumpf, CW Siyasiya
Mechanical alloying of an equiatomic mixture of crystalline Ti and Pt
elemental powders in a high-energy ball mill formed 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-to-powder weight ratio, for time intervals of 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 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 did not exceed the crystallization
temperature of the alloy.
Keywords: TiPt alloy, mechanical alloying, amorphization, solid-state reactions.