High temperature mechanical properties of Ti-47Al-2Cr (at %) alloy produced using powder compact forging of a mechanically milled powder

Abstract

Ultrafine grained (UFG) Ti-47Al-2Cr (at %) alloy was prepared using a combination of high energy ball milling of a mixture of elemental powders to produce a Ti/Al/Cr composite powder and forging of compacts of this composite powder. The microstucture of the powder forged alloy was found to be dependent on the initial condition of the powder. The alloy produced by this method has demonstrated good formability, both in tensile and compression testings at elevated temperatures. A ductility of 80-165% in tension has been observed, while in a compression plastic strain of ∼ 50% was found to be easily achievable, without causing cracking. The deformation behaviour of the particular alloy in tension and compression at elevated temperature has been discussed in detail. The results from the present investigation indicate that UFG Ti-47Al-2Cr (at %) alloy produced using powder compact forging has good formability, and is suitable precursor for near-net shaping using thermomechanical processes such as forging and superplastic forming. © 2009 IOP Publishing Ltd.