Effect of Isothermal Forging on the Microstructure and Properties of Ti‐17 Titanium Alloy Prepared by Different Powder Compaction Methods

Abstract

The isothermal forging was utilized to improve the microstructure and properties of three kinds of Ti-17 titanium powder compacts which were prepared through vacuum sintering (VS-ing), laser sintering (LS-ing) and hot isostatic pressing (HIP-ing). In order to fully densify the powder compact and simultaneously improve the microstructure, the isothermal forging was conducted above and below the beta transus temperature of powder compact. After isothermal forging, the residual pores existed in microstructure of VS-ed Ti-17 titanium powder compact are fully closured. The microstructure with coarse columnar beta grains of LS-ed Ti-17 titanium powder compact transforms into bimodal microstructure with lamellar and equiaxed alpha phases. The microstructure with primary coarse grains of HIP-ed Ti-17 titanium powder compact are thoroughly broken and transformed into equiaxed microstructure. The mechanical properties of all three kinds of Ti-17 titanium powder compacts are significantly improved.