定向凝固Ni_3Al合金高温变形行为的研究

HIGH TEMPERATURE DEFORMATION BEHAVIOURS OF DIRECTIONALLY SOLIDIFIED Ni3Al ALLOY

定向凝固（ＤＳ）Ｎｉ３Ａｌ合金在１０００至１０５０℃温区，应变速率为２．１×１０（－４）ｓ（－１）时，应变速率敏感指数ｍ大于０．３，最大延伸可达１８５％，具有超塑变形的行为待征．金相及电子显微镜观察表明：超塑变形后，原始柱状晶内有亚结构及新晶粒生成。认为ＤＳＮｉ３Ａｌ高温变形后发生了动态再结晶过程，并由此导致ＤＳＮｉ３Ａｌ合金呈现超塑现象．

Directionally solidified (DS) Ni3Al alloy exhibits superplasticity under a strain rate of 2.1×10(-4) s(-1) in the temperature range from 1000 to 1050℃. The highest of strain rate m value may exceed 0.3 and a maximum elongation is 1 85%. Optical and TEM observations revealed that a dynamic recrystallization process took place and this process was then in turn resulted in superplasticity of DS Ni3Al alloy.