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定向凝固AlCoCrCuFeNi高熵合金的组织与力学性能
Microstructure and Mechanical Properties of Directionally Solidified AlCoCrCuFeNi High-entropy Alloy
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- DOI:
- 作者:
- 邓妮,闫育洁,梁航,魏晨,贺一轩,王军
DENG Ni, YAN Yujie, LIANG Hang, WEI Chen,HE Yixuan
- 作者单位:
- 西北工业大学
State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072, China
- 关键词:
- 高熵合金;定向凝固;组织演变;Cu偏析;硬度
High-entropy alloy; Directional solidification; Microstructure evolution; Cu segregation; Hardness
- 摘要:
- 以AlCoCrCuFeNi高熵合金为研究对象,系统研究了不同抽拉速率下合金定向凝固组织演变规律、Cu偏析及力学性能。结果表明,定向凝固AlCoCrCuFeNi高熵合金仍然为稳定的BCC和FCC双相结构,微观组织由富FeCoCr相、富AlNi相和富Cu相组成。随着抽拉速率的增大,所获的凝固组织由粗大的树枝晶逐渐演变为细长的层状树枝晶,枝晶臂间距显著减小。不同抽拉速率下,富Cu相都偏析于枝晶间,其在富FeCoCr相边界处形成不连续的锯齿状分布且在富AlNi相中形成富Cu沉淀。随着抽拉速率的增大,富Cu沉淀由亚微米级转变为纳米级,富Cu相中的Cu原子浓度下降。合金中各部分组织的显微维氏硬度差异随抽拉速率的增大而减小,平均显微维氏硬度从358 HV增加到375 HV。
The effect of different drawing velocities on microstructure, Cu segregation and mechanical property of AlCoCrCuFeNi high-entropy alloy by directional solidification was studied. Results show that AlCoCrCuFeNi high-entropy alloy still has stable BCC and FCC structure after directional solidification, and its microstructure is composed of FeCoCr-rich, AlNi-rich and Cu-rich phases. With the increase of the drawing rate, the morphology of the solidified microstructure gradually changes from coarse dendrites to elongated lamellar-dendrites, and the distance between dendrite arms decreases significantly. Under different drawing rates, Cu-rich phase tend to form interdendritic segregation, and discontinuous zigzag distribution is formed at the boundary of FeCoCr phase and Cu-rich precipitate is formed in AlNi-rich phase. With the increase of the drawing rate, the Cu-rich precipitate changes from submicron to nanometer scale, and the concentration of Cu atoms in the Cu-rich phase decreases. The micro-vickers hardness difference of each region of the alloy decreases with the increase of the drawing rate, and the average micro-vickers hardness increases from 358 HV to 375 HV.