退火热处理对等径角挤压回收Ti-6Al-4V合金微观结构和显微硬度的影响

采用等径角挤压法回收Ti-6Al-4V合金切屑,并研究了回收样品和退火处理样品的微观结构和显微硬度。结果表明:在回收样品中,切屑之间的边界依然存在,而由于剧烈塑性变形,超细晶结构和较强的纤维织构得以形成。退火处理后,切屑边界部分消失,超细晶组织部分再结晶;而与此同时,退火处理样品展现出更宽泛的织构,再结晶晶粒并不存在择优取向。值得注意的是,退火处理样品的显微硬度较回收样品略有升高。

Effect of Annealing Treatment on Microstructure and Micro-hardness of Equal Channel Angular Pressing Recycled Ti-6Al-4V

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-hard-ness tests upon the as-recycled Ti-6Al-4V as well as the sample experienced subsequent annealing treatment were carried out.We ob-served that the prior chip boundaries remained in the recycled material,and the severe plastic deformation contributed to the forma-tion 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 distri-bution 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.