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采用电子背散射衍射技术,研究了室温下CoCrFeMnNi高熵合金在单向拉伸(真应变量为0%~12.4%)过程中的组织和取向演变。结果表明,初始组织表现为等轴晶形貌,退火孪晶形成于等轴晶粒内;拉伸后,等轴晶粒被拉长,小角度晶界急剧增多且主要分布在细小孪晶界和大角度晶界附近。该合金通过位错滑移的方式协调其室温下的拉伸变形。在变形过程中,晶粒取向不均匀转动,但晶粒内基体和孪晶的取向大体上沿着相同的方向转动,基体拉伸轴的转动规律为,反极图<112>和<111>附近的基体拉伸轴向<111>方向转动,符合Taylor模型;反极图中心和<101>附近的基体拉伸轴向<001>-<111>连线转动,符合Sachs模型;反极图<001>附近的基体拉伸轴转动无明显规律。
The structure and orientation evolution of CoCrFeMnNi high entropy alloys at room temperature under uniaxial tension (true strain 0% ~ 12.4%) were studied by using electron backscatter diffraction technique. The results show that the initial microstructure is equiaxed and the annealing twin forms in the equiaxed grains. After stretching, the equiaxed grains are elongated and the small-angle grain boundaries increase sharply and are mainly distributed in the fine twin boundaries And near the large-angle grain boundaries. The alloy coordinates its tensile deformation at room temperature by means of dislocation slip. In the deformation process, the grain orientation is not uniform rotation, but the orientation of the matrix and twin in the grain generally rotates in the same direction. The rotation law of the stretching axis of the matrix is the reverse polar diagram <112> and <111> Near the substrate stretching axis <111> direction, in line with the Taylor model; reverse polar center and <101> near the substrate stretching axis <001> - <111> line rotation, consistent with the Sachs model; In the vicinity of <001>, there is no obvious rule for the rotation of the substrate.