Ti-Mg alloy powder synthesis via mechanochemical reduction of TiO2 by elemental magnesium

Abstract

This paper reports the preliminary results of an investigation on the synthesis of a Ti-Mg alloy powder through mechanochemical processing of TiO2 and Mg powders. TiO2 was mixed with elemental Mg according to a nominal stoichiometric composition with 15% excess Mg. The powder mixture was mechanically milled in a Simoloyer high energy ball mill for 5 different durations. Contamination was minimised by processing under a high purity argon atmosphere. Changes in phase composition were studied by XRD techniques. TiO2 was reduced, as shown by the formation of MgO. The extent of the reduction, as indicated by XRD peaks’ intensities, increased with milling time. XRD spectra of powders milled for 24 hours revealed virtual disappearance of TiO2 peaks and there was no evidence of elemental Ti. The lattice parameter of the resulting Ti metal was larger than that of elemental Ti. This implies that the Ti was alloyed with free Mg to produce Ti-Mg alloy powder. The lattice parameter increased with increasing milling time.