退火处理对3D打印CoCrFeMnNi高熵合金组织和性能的影响

采用选区激光熔化(SLM)工艺制备了等原子比CoCrFeMnNi高熵合金,并对试验合金分别进行了650 ℃×1 h和900 ℃×1 h的退火处理。结合微观组织分析、拉伸性能分析和断裂特征分析,研究了退火工艺对SLM制备的CoCrFeMnNi高熵合金组织和力学性能的影响。结果表明:打印态试样屈服强度、抗拉强度和伸长率分别为672 MPa、751 MPa和34.3%。650 ℃×1 h退火处理后,屈服强度、抗拉强度和伸长率略微降低,分别为583 MPa、718 MPa和33.5%。900 ℃×1 h退火处理后屈服强度和抗拉强度分别降低至494 MPa和707 MPa,伸长率提高至46.6%。断口呈典型的韧窝特征,变形机制均为纳米孪生。

Effect of annealing treatment on microstructure and properties of 3 D printed CoCrFeMnNi high-entropy alloy

Equimolar CoCrFeMnNi high-entropy alloy (HEA) was prepared by using selective laser melting (SLM) process, and the tested alloy was annealed at 650 ℃ and 900 ℃ for 1 h, respectively. Combined with microstructure, tensile properties and fracture characteristics analysis, effect of annealing process on microstructure and mechanical properties of CoCrFeMnNi HEA prepared by SLM was studied. The results show that the yield strength, tensile strength and elongation of the as-printed specimen are 672 MPa, 751 MPa and 34.3%, respectively. After annealing at 650 ℃ for 1 h, the yield strength, tensile strength and elongation decrease slightly, which are 583 MPa, 718 MPa and 33.5%, respectively. After annealing at 900 ℃ for 1 h, the yield strength and tensile strength decrease to 494 MPa and 707 MPa, respectively, while the elongation increases to 46.6%.The fracture surface shows typical dimple characteristics, and the deformation mechanism is nano-twinning.