Effect of cooling rate on microstructure and deformation behavior of Ti-based metallic glassy/crystalline powders

The microstructures and deformation behavior of Ti-based metallic powders were comprehensively investigated. It has been found that, with increasing the powder size, the phase constituent alters from pure glassy to glassy with crystalline phases (face centered cubic structured NiSnZr and hexagonal structured Ti3Sn phases). Our results suggest that the synergetic effect of the thermodynamics and kinetics determines the subsequent characteristics of the crystalline precipitations. Through comparative nanoindentation tests, it was found that the small powders exhibit more pop-in events and a larger pile-up ratio, suggesting that the plastic deformation of the metallic powders is governed by the combined effects of the free volume and the crystallization, which are determined by the cooling rate.