Viscous flow during spark plasma sintering of Ti-based metallic glassy powders

Viscous flow has rarely been observed in solid-state sintering of metal, while operates the dominant mass transport mechanisms in vitreous materials. In the present study, Ti-based bulk metallic glasses (BMGs) with nearly 100% relative density were fabricated by spark plasma sintering of a gas-atomized Ti48Ni32-Cu8Si8Sn4 glassy alloy powder. Two main shrinkage stages of densification occurred at a constant heating rate. Based on the analysis of experimental data and microstructure observations of samples sintered at various temperatures, sintering mechanisms are proposed for the sintering of Ti-based metallic glassy powders in light of the viscous flow model. (c) 2013 Elsevier B.V. All rights reserved.