DEVELOPMENT STUDY OF BCC-TYPE LIGHT SUPPERALLOY WITH HIGH RESISTANCE TO CORROSION AND ENVIROMENT OXIDATION

用X射线衍射仪和透射电子显微镜研究了CoTi与Co2AlTi金属间化合物界面位错的微观结构和形态。并通过拉伸和压缩试验研究了其高温力学性能。B2型CoTI单相多晶合金的拉伸屈服强度与压缩试验结果一致，表现出反常的正温度依赖性。但在整个试验温度范围内，拉伸屈服应力值均低于压缩试验值。所有试件的断裂方式均为解理断裂和脆性断裂。在掺杂2at.%Al的CoTi合金中没有观察到Co2AlTi相的析出。Al加入量超过3at%时，可观察到Co_2AlTi的针状析出和界面位错。

The microstuructre and morphology of interfacial dislocation between CoTi and Co_2AlTi intermetallic are investigated by X-ray diffraction and transmission electron microscopy. And also, high temperature mechanical properties are investigated by tensile and compression test. The B2 type CoTi single phase polycrystal alloy exhibits the anomalous positive temperature dependence of the tensile yield strength as same as the result obtained by compression test. However, the values of tensile yield stress were lower than those of the compression test in whole test temperature. The fracture mode of all tested specimens showed cleavage and brittle fracture. It was not observed the precipitation of Co_2AlTi in CoTi alloy doped by 2at.%Al. And the acicular precipitation of Co_2AlTi with interfacial dislocations was observed in the specimen added over 3at.%Al.