Microstructure Evolution and Properties of Ti-xFe (x=1%, 5%, 10%, 15%) Alloys Prepared by Vacuum Sintering and Hydrogen Induced Phase Transformation Sintering

After cold isostatic pressing formation of HDH-Ti powder and carbonyl Fe powder as raw materials, Ti-xFe alloys (x=1%, 5%, 10%, 15%, mass fraction) were prepared by vacuum sintering and hydrogen induced phase transformation sintering (HSPT). The density, phase, microstructure evolution and microhardness of the alloys in the two sintering processes were compared. The results show that the HSPT alloy contains more pores and the density is significantly lower than that of the vacuum sintered alloy. The content of β phase in the two alloys increases with the increase of Fe content, and TiFe phase appears only in the Ti-15Fe alloy prepared by HSPT. During the preparation of HSPT alloy, H has a significant inhibitory effect on the diffusion of Fe. When Fe content is no less than 5%, short rod-like or needle-like secondary α phase is precipitated inside the β phase of the alloy after dehydrogenation, which makes the β phase structure fine. When Fe content reaches 10% or higher, significant enrichment of Fe appears. At the same time, H leads to coarseningof the β phase, and the β phase coarsening is more obvious with the increase of Fe content. The microhardness of HSPT alloy is higher than that of the vacuum sintered alloy, especially that of α phase increases linearly with the increase of Fe content. © 2020, Science Press. All right reserved.