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

Abstract

View the article online for updates and enhancements. 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. IntroductionTiAl based alloys are considered as promising materials for elevated temperature applications such as advanced gas turbines, because of the combination of low density, high specific modulous and strength retention [1]. The processing and mechanical behaviour of this novel class of materials have been a subject of intense research in the last two decades [2,3]. Although a few studies have reported the deformation behaviour of UFG TiAl based alloys [4], a lot of work has yet to be done in this field to gain in-depth understanding of the effects of different factors. In the present study the elevated temperature mechanical properties of UFG Ti-47Al-2Cr (at %) alloy produced using powder compact forging has been elaborated by conducting tensile and compression testing at an elevated temperature-900 o C.