Microstructure and Properties of High Temperature Titanium Alloys with a High Si Content Prepared by Powder Metallurgy

Abstract

The objective of this paper is to improve the performance of high temperature titanium alloys with a high Si content by powder metallurgy. Firstly Ti-6.5Al-1.4Si-2Zr-0.5Mo-2Sn alloy powders were prepared using two different rotating speeds by plasma rotating electrode process (PREP). Then two sintering temperatures were selected to fabricate titanium alloys by hot isostatic pressing (HIP). The relationship between rotating speed and particle size distribution was investigated. X-ray diffraction, SEM, and OM were used to characterize the phase compositions, morphologies, and microstructures of the powders and titanium alloys. The mechanical properties of titanium alloys were investigated at room temperature,300℃ and 600℃. The results show that high quality titanium alloy powders were prepared by PREP. The mechanical properties of titanium alloy fabricated by powder metallurgy were superior compared to casting.And the strength is higher than typical Ti-1100 high temperature alloy.

Fig. 6 SEM images of HIPed titanium alloys at sintering temperature of (a) 940℃ and (b) 980℃.