Heterogenous columnar-grained high-entropy alloys produce exceptional resistance to intermediate-temperature intergranular embrittlement
Heterogenous columnar-grained high-entropy alloys produce exceptional resistance to intermediate-temperature intergranular embrittlement
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异质柱晶高熵合金具有优异的中温沿晶脆性
DOI：
10.1016/j.scriptamat.2020.11.007
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发表时间：
2021-03-15
影响因子：
6
通讯作者：
Liu, C. T.
中科院分区：
文献类型：
--
作者：
Cao, B. X.;Kong, H. J.;Liu, C. T.
高熵合金（HEAs）增强相干纳米粒子显示出很大的潜力，高温结构的应用，然而，通常遭受严重的晶间脆化时，在中间温度下测试。在这项研究中，我们展示了一种新的“异质柱状颗粒”（HCG）的方法，可以有效地克服这个棘手的问题。与在800 ℃时沿晶界沿着表现出极端脆性的等轴对应物不同，新开发的HCG-HEA表现出对源自独特晶界特征和分布的沿晶断裂的异常高的抵抗力。不均匀柱状晶粒结构的存在显著抑制了裂纹成核和沿着边界的扩展，导致在800 ℃下类似于18. 4%的异常大的拉伸延展性与类似于652 MPa的高屈服强度组合。这一发现为具有非凡机械性能的高温材料的创新设计提供了新的见解。(C)2020 Acta Materialia Inc.由爱思唯尔有限公司出版。保留所有权利。
High-entropy alloys (HEAs) strengthened by coherent nanoparticles show great potentials for elevated-temperature structural applications, which however, generally suffer from a severe intergranular embrittlement when tested at intermediate temperatures. In this study, we demonstrated a novel "heterogenous columnar-grained"(HCG) approach that can effectively overcome this thorny problem. Different from the equiaxed counterpart which shows extreme brittleness along grain boundaries at 800 degrees C, the newly developed HCG-HEA exhibits an exceptionally high resistance to intergranular fractures originating from the unique grain-boundary characters and distributions. The presence of heterogenous columnar grain structure drastically suppresses the crack nucleation and propagation along with boundaries, resulting in an unusually large tensile ductility of similar to 18.4 % combined with a high yield strength of similar to 652 MPa at 800 degrees C. This finding provides a new insight into the innovative design of high-temperature materials with extraordinary mechanical properties. (C) 2020 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.