Ni-42Al单相金属间化合物的超塑性  

The Superplasticity in Large-grained Ni-42Al Intermetallics

作　　者：胡静[1] 林栋樑[1] 

机构地区：[1]上海交通大学材料科学与工程学院高温材料及高温测试教育部重点实验室

出　　处：《上海交通大学学报》2006年第10期1731-1734,共4页Journal of Shanghai Jiaotong University

基　　金：国家自然科学基金资助项目(59895150)

摘　　要：研究了原始晶粒尺寸为200μm的富Ni单相Ni-42Al金属间化合物的高温变形行为及组织演变规律.结果表明,该合金在1 000~1 100℃、应变速率(0.125~2)×10-3s-1内呈现超塑性变形,在1 075℃、应变速率为10-3s-1时,最大延伸率可达306%.研究发现,该合金的应变速率敏感指数m与应变温度及应变速率相关.实验条件下,m值在0.2~0.3变化.显微结构分析表明,原始大晶粒组织经超塑性变形后显著细化,大晶粒超塑性变形是通过位错的交滑移与攀移等交互作用发生的连续动态回复和再结晶导致的.The high temperature deformation behavior of single phase Ni-42Al intermetallics with initial grain size of 200 μm was examined.It was found that the alloy exhibits superplastic behavior under an initial strain rate of(0.125～2)×10^(-3) s^(-1) at 1 000～1 100℃.A maximum elongation of 306% was obtained at 1 075℃.The strain rate sensitivity m value is correlated with the temperature and initial strain rate,being in the range of 0.2～0.3.The optical metallography(OM) shows that the grains are refined during superplastic deformation from initial 200 μm to less than 20 μm.The electron back-scattered diffraction(EBSD)and transmission electron microscopy(TEM) observations show that an unstable subgrain boundary network forms during the superplastic deformation. The subgrain boundaries are transformed into low and high angle grain boundaries by absorbing gliding dislocations.The large grained superplastic phenomenon can be explained by continuously dynamic recovery and recrystallization(CDRR).

关 键 词：二元NiAl 金属间化合物 大晶粒 超塑性 回复与再结晶 

分 类 号：TG135.1[一般工业技术—材料科学与工程]