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采用反重力真空吸铸技术,制备致密且组织演变明显的AlCoCrFeNiTi0.5高熵合金,研究凝固过程中高熵合金的组织结构转变规律。结果表明:从合金的边缘到中心,随着凝固的进行,合金的组织结构发生规律性转变;边缘区域为衍射峰强度相近的bcc1相和bcc2相,之后bcc2衍射峰强度降低,在中心区域合金析出σ相;从边缘到中心,组织由细小的晶粒转变为树枝晶组织,且晶粒尺寸一直呈长大趋势,在中心区域,树枝晶间析出细小的球状σ相;随着晶粒的长大,合金的硬度降低,但中心区域由于析出σ相,虽然晶粒尺寸最大,合金具有最高的硬度。
The anti-gravity vacuum suction casting technique was used to prepare dense AlCoCrFeNiTi0.5 high-entropy alloys with obvious microstructure evolution and to study the transformation regularity of high-entropy alloys during solidification. The results show that the microstructures of bcc1 phase and bcc2 phase are similar to each other in the edge region, and the bcc2 diffraction peak intensity decreases after the solidification proceeds. In the central region of the alloy From the edge to the center, the microstructure changes from small grains to dendrites, and the grain size tends to grow up. In the central region, fine spherical σ phase precipitates between the dendrites. With the increase of grain size Grow, the hardness of the alloy decreases, but the central region due to the precipitation of σ phase, although the largest grain size, the alloy has the highest hardness.