层片状双相TiAl合金拉伸与压缩变形行为差异  

DIFFERENCE OF DEFORMATION BEHMIORS OF TiAl POLYSYNTHETICALLY TWINNED CRYSTALS IN TENSION AND COMPRESSION AT ROOM TEMPERATURE

作　　者：姚可夫[1] 乾晴行[1] 山口正治 

机构地区：[1]清华大学机械系,北京100084 [2]京都大学工学部

出　　处：《金属学报》2000年第3期308-312,共5页Acta Metallurgica Sinica

基　　金：日本文部省和国家教育部基金资助项目

摘　　要：Ｓ本文研究了层片状双相ＴｉＡｌ合金的室温拉伸压缩变形行为与断裂行为，发现在拉压变形条件下，其室温塑性有显著差异．并且这种差异与裂纹扩展路径有关．在室温拉伸与压缩变形时，该合金的拉压屈服应力随外载与层片界面间的夹角ψ的变化趋势一致，而拉压断裂应变εｆ随夹角ψ的变化趋势正好相反．外载与层片界面垂直时（ψ＝９０°），拉伸断裂应变最小（εｆ≈０）；压缩断裂应变最大（εｆ≈３８％）．夹角ψ减小时，拉伸断裂应变增加，压缩断裂应变减小在拉、压变形时裂纹的扩展路径不同。The deformation and fracture behaviors, in tension and in compression, of a TiAl-V alloy with polysynthetically twinned(PST) structure have been studied. It has been found that the room temperature ductilities in tension and in compression are quite different and this difference is closely related to the crack propagating way. When loading axis is perpendicular to the lamellar boundary (-90°), fracture stain is almost zero in tension while it is the largest one in compression. When the angle W between loading axis and the lamellar boundary decreases, fracture strain increases in tension but decreases in compression. When =90°, cracks tend to propagate along lamellar boundaries in tension while they tend to propagate across lamellar boundaries in compression. However, when =0°, cracks tend to propagate across the lamellar boundary in tension while they tend to propagate along the lamellar boundary in compression. The influence of crack propagating way and resolved normal stress component of extra stress on the ductility has been discussed.

关 键 词：双相TiAl合金 层片界面 断裂应变 裂纹扩展 

分 类 号：TG146.2[一般工业技术—材料科学与工程]