Effects of Mo on the evolution of microstructures and mechanical properties in Co-Al-W base superalloys
Effects of Mo on the evolution of microstructures and mechanical properties in Co-Al-W base superalloys
复制标题
DOI：
10.1016/j.msea.2018.11.087
复制
发表时间：
2019-02
期刊：
影响因子：
--
通讯作者：
J. Liu;J. Yu;Y.H. Yang;Y.Z. Zhou;X.F. Sun
中科院分区：
文献类型：
--
作者：
J. Liu;J. Yu;Y.H. Yang;Y.Z. Zhou;X.F. Sun
研究了两种不同钨钼加入量的Co-Al-W基高温合金的凝固路径、组织和力学性能。Mo的加入不影响γ‘相的体积分数，但γ’相的形态由立方体转变为近立方体。在两种合金体系中都发现了μ相和β相。虽然Mo的加入降低了μ相的熔点，但凝固路径保持不变：L→L1+ γ→L2+ γ + μ→γ + μ + β→γ + μ + β + γ‘。在Co-Al-W合金系统中，γ‘相包络在枝晶间区域的析出还未见报道。在热处理过程中，元素在第二相和基体之间的扩散导致了周围γ‘相的形成。在两种合金中，μ相的显微硬度最高，其次是β相和基体的显微硬度，这一点很容易受到Mo添加的影响。在断裂过程中，μ相中产生了微裂纹，且随着Mo加入量的增加，微裂纹的数量增加。
The solidification paths, microstructures and mechanical properties of two Co-Al-W base superalloys with different additions of tungsten and molybdenum were investigated. Mo addition does not influence the volume fraction of the γ′ phase; however, the morphology of the γ′ phase changes from cuboidal to near cuboidal. The μ phase and β phase were identified in both alloy systems. Although the melting point of the μ phase is decreased by Mo addition, the solidification paths remain the same: L→ L1+ γ → L2+ γ + μ → γ + μ + β → γ + μ + β + γ′. The precipitation of a γ′ phase envelop around the interdendritic regions in Co-Al-W alloy systems has never been reported. The formation of a surrounding γ′ phase was caused by the diffusion of elements between secondary phases and the substrate during the heat treatments. The microhardness of the μ phase, which can be easily influenced by Mo addition, is the highest in both alloys, followed by the microhardnesses of the β phase and the substrate. In the fracturing process, microcracks were generated in the μ phase, the number of which increased with Mo addition.