Abstract: The present study concerns the change in microstructure and micro-hardness induced by annealing treatment for Ti-6Al-4V machining chips recycled by using equal channel angular pressing (ECAP). The microstructure exploration and micro-hardness tests upon the as-recycled Ti-6Al-4V as well as the sample experienced subsequent annealing treatment were carried out. We observed that the prior chip boundaries remained in the recycled material, and the severe plastic deformation contributed to the formation of the ultrafine grained microstructure and a strong fibre-like texture. After annealing, the chip boundaries partially dissolved and the fine grains partially recrystallized. Meantime, the annealed material exhibited a weaker texture and a wider orientation distribution was found for the recrystallized grains. It is noteworthy that the micro-hardness remained essentially unchanged, even slightly increased for the recycled Ti-6Al-4V after heat treatment.
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2018, Vol. 32 
