原位碳化物增强CoCrFeMnNi高熵合金的组织与性能

Microstructure and Properties of In-situ Carbide Enhanced CoCrFeMnNi High-entropy Alloy

采用热压烧结制备了不同石墨含量的CoCrFeMnNi高熵合金,研究了石墨对合金组织和力学性能的影响。结果表明,加入石墨后,烧结体中原位生成了M_(23)C_(6)型富Cr碳化物,并弥散分布于基体中。随石墨含量增加,碳化物尺寸保持不变,面积分数呈抛物线状增加,烧结体屈服强度随之增加。合金屈服强度增量满足Δσ=31.5+762(f^(1/2)/r),其主要强化机制为碳化物的弥散强化。当石墨含量为1%时,合金具有优异的综合力学性能,其屈服强度、抗拉强度和伸长率分别为338 MPa、672 MPa和20.9%。

CoCrFeMnNi-rC alloys were fabricated via hot-pressing sintering,and effects of graphite on the microstructure and mechanical properties of the alloys were mainly investigated.The results indicate that a M_(23)C_(6) type Cr-rich carbide is in-situ formed in sintered bulks and dispersedly distributed in the matrix.With graphite content increase,the size of carbide is stable,while the area fraction is increased in a parabola,resulting in an increase in yield strength of the sintered bulks.The increase of yield strength conforms Δσ=31.5+762(f^(1/2)/r),and the main strengthening mechanism is attributed to dispersion strengthening of the carbide.The alloy exhibits excellent comprehensive mechanical properties χ=1%,where the yield strength,tensile strength and elongation are 338 MPa,672MPa,and 20.9%,respectively.