Synthesis of nanoparticles of titanium aluminides by hydrogen plasma–metal reaction: effects of master alloy composition and chamber pressure on particle size, composition and phase

Abstract

Hydrogen plasma–metal reaction (HPMR) method is applied successfully for large scale synthesis of nanoparticles of titanium aluminides, from binary Ti–Al master alloys with Al content varying from 5 to 75 at-%. The average size, phase constitution and chemical composition of the as synthesised nanoparticles are characterised and related to the master alloy composition and processing parameters. Results show that Al content in the as synthesised nanoparticles deviates positively from that of the master alloy. The maximum generation rates of Al and Ti occur at Al content about 35 and 20 at-% in the master alloy respectively. The average size of the nanoparticles increases with increasing Al content in the master alloy, with a peak at 35–45 at-%; for the same Al content, it increases with increasing chamber pressure and saturates at the chamber pressure of 0.080 MPa.