Achieving an excellent combination of strength and ductility in a single-phase metastable medium-entropy alloy
Achieving an excellent combination of strength and ductility in a single-phase metastable medium-entropy alloy
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DOI：
10.1016/j.jmrt.2023.10.242
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发表时间：
2023-11
期刊：
影响因子：
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通讯作者：
Caixia Wang;Ruixin Sheng;Dawei Zhou;Weidong Li;Shuying Chen;Fanchao Meng;G. Velişa;Daiyi Chao;Liang Jiang;Peter K. Liaw;Yang Tong
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文献类型：
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作者：
Caixia Wang;Ruixin Sheng;Dawei Zhou;Weidong Li;Shuying Chen;Fanchao Meng;G. Velişa;Daiyi Chao;Liang Jiang;Peter K. Liaw;Yang Tong
开发能够在低温下保持高强度和延展性的坚固合金一直是长期追求的目标，特别是对于极低温环境中的承载应用。在这项研究中，我们报道了一种新开发的面心立方（FCC）亚稳（Ni 0·3Co 0·4Cr 0. 3）94 Mo 6中熵合金（Mo-MEA），其在77 K下具有优异的强度和延展性的协同作用，超过了最坚韧的等原子NiCoCr MEA。与等原子NiCoCr MEA相比，Mo-MEA表现出屈服强度显著增加68%（从407到685 MPa），极限拉伸强度适当增加10%（从1289到1415 MPa），沿着延伸率从75%增加到78.45%。电子背散射衍射和透射电子显微镜揭示了激活的多峰变形机制，包括位错，堆垛层错，孪生，和FCC到六方密堆积相变，在77 K的拉伸变形。
The development of robust alloys capable of maintaining high strength and ductility at cryogenic temperatures has been a long-sought goal, particularly for load-bearing applications in extremely low-temperature environments. In this study, we reported a newly developed face-centered-cubic (FCC) metastable (Ni0·3Co0·4Cr0.3)94Mo6medium-entropy alloy (Mo-MEA) with an excellent synergy of strength and ductility at 77 K, surpassing the toughest equiatomic NiCoCr MEA. Compared to the equiatomic NiCoCr MEA, the Mo-MEA exhibited a substantial increase in yield strength by 68 % (from 407 to 685 MPa) and a decent enhancement of the ultimate tensile strength by 10 % (from 1289 to 1415 MPa), along with a marginal increase in elongation from 75 % to 78.45 %. Electron backscatter diffraction and transmission electron microscopy revealed the activation of multimodal deformation mechanisms, including dislocations, stacking faults, twinning, and FCC-to-hexagonal-close-packed phase transformation, during the tensile deformation at 77 K.