Refractory high-entropy alloys (RHEAs) have attracted considerable interest due to their elevated melting points and remarkable softening resistance. Nevertheless, the ambient-temperature brittleness and inadequate high-temperature oxidation resistance commonly limit the application of the body-centered-cubic (BCC) RHEAs. In this study, we achieved a TiVHfNbCrAl RHEA with a desirable yield strength of ∼1178 MPa and tensile ductility of ∼19.5 %. Exploring the underlying mechanisms, we demonstrated that Cr and Al alloying induced a nanoscale spinodal structure and generated a significant lattice misfit, resulting in a notable strengthening effect and pinning behavior. Meanwhile, dislocation configurations involving loops and cross slips were stimulated by pinning, serving a reliable strain-hardening capability to large strains. Significantly, Cr and Al alloying improved oxidation resistance and prevented severe spallation at high temperatures by forming protective oxide layers. These results provide opportunities to design novel RHEAs.

中文翻译：

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通过 Cr 和 Al 合金化，将耐火高熵合金的优异机械性能与抗氧化性结合在一起

难熔高熵合金（RHEA）由于其高熔点和显着的抗软化性而引起了人们的极大兴趣。然而，常温脆性和不足的高温抗氧化性通常限制了体心立方（BCC）RHEA的应用。在这项研究中，我们获得了 TiVHfNbCrAl RHEA，其屈服强度约为 1178 MPa，拉伸延展性约为 19.5%。通过探索潜在机制，我们证明了 Cr 和 Al 合金化诱导了纳米级旋节线结构并产生了显着的晶格失配，从而产生了显着的强化效应和钉扎行为。同时，通过钉扎激发了涉及环和交叉滑移的位错配置，为大应变提供了可靠的应变硬化能力。值得注意的是，Cr 和 Al 合金化提高了抗氧化性，并通过形成保护性氧化层来防止高温下的严重剥落。这些结果为设计新颖的 RHEA 提供了机会。