Superior High-Temperature Strength in a Supersaturated Refractory High-Entropy Alloy
Superior High-Temperature Strength in a Supersaturated Refractory High-Entropy Alloy
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DOI：
10.1002/adma.202102401
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发表时间：
2021-10-08
影响因子：
29.4
通讯作者：
Liaw, Peter K.
中科院分区：
文献类型：
--
作者：
Feng, Rui;Feng, Bojun;Liaw, Peter K.
难熔高熵合金（RHEAs）在高温下具有广阔的应用前景。然而，由于热软化，在高于1173K的高温下实现高强度仍然具有挑战性。采用本征材料特性作为合金设计原则，设计了一种具有高温强度（1273 K时超过1000 MPa）的单相体心立方（BCC）CrMoNbV RHEA合金，该合金上级性能优于其它已报道的RHEA合金和传统高温合金。的起源的高温强度揭示了原位中子散射，透射电子显微镜，和第一性原理计算。的CrMoNbV的高温强度保留高达1273 K，来自其大的原子尺寸和弹性模量失配，不敏感的温度依赖性的弹性常数，和主导地位的非螺旋字符位错所造成的强溶质钉扎，这使得固溶强化显着。本研究中的合金设计原则和见解为设计具有出色高温强度的RHEA铺平了道路。
Refractory high-entropy alloys (RHEAs) show promising applications at high temperatures. However, achieving high strengths at elevated temperatures above 1173K is still challenging due to heat softening. Using intrinsic material characteristics as the alloy-design principles, a single-phase body-centered-cubic (BCC) CrMoNbV RHEA with high-temperature strengths (beyond 1000 MPa at 1273 K) is designed, superior to other reported RHEAs as well as conventional superalloys. The origin of the high-temperature strength is revealed by in situ neutron scattering, transmission-electron microscopy, and first-principles calculations. The CrMoNbV's elevated-temperature strength retention up to 1273 K arises from its large atomic-size and elastic-modulus mismatches, the insensitive temperature dependence of elastic constants, and the dominance of non-screw character dislocations caused by the strong solute pinning, which makes the solid-solution strengthening pronounced. The alloy-design principles and the insights in this study pave the way to design RHEAs with outstanding high-temperature strength.