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

用X射线衍射和透射电镜研究了CoTi与Co_2AlTi金属间化合物界面位错的微观结构和形貌。并通过拉伸和压缩试验研究了其高温力学性能。B_2型CoTi单相多晶合金的拉伸屈服强度与温度呈反常的正相关关系，与压缩试验结果一致。但在整个试验温度范围内，拉伸屈服应力均低于压缩屈服应力。所有试样的断裂方式均为解理断裂和脆性断裂。在掺杂量为2at.%的CoTi合金中，没有观察到Co_2AlTi相的析出添加量超过3at.%时，出现了Co_2AlTi相的针状析出，并伴有界面位错Al.

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.