Blended elemental P/M synthesis and property evaluation of Ti-1100 alloy

Abstract

A near α type Ti-1100 alloy (Ti–6Al–2.75Sn–4Zr–0.4Mo–0.4Si) was produced by the blended elemental (BE) powder metallurgy (P/M) method using extra low chlorine (ELCL) hydride–dehydride (HDH) titanium powder and master alloy powder with a particle size smaller than 150 μm. The conventional BE P/M method produced a fine grain-size (150 μm in diameter) colony microstructure, whereas the new BE P/M method, in which a heat treatment step is added prior to final hot isostatic pressing (HIP'ing), produced a fine grain-size acicular microstructure. Mechanical properties such as tensile strength at room temperature and at elevated temperature, high cycle fatigue (HCF) strength at room temperature, and creep were evaluated for both colony and acicular microstructures. Further, a property comparison was made between the present BE P/M Ti-1100 and previously reported BE P/M titanium alloys such as Ti–6Al–2Sn–4Zr–2Mo and Ti–6Al–4V.