Ab initio-predicted micro-mechanical performance of refractory high-entropy alloys.
Ab initio-predicted micro-mechanical performance of refractory high-entropy alloys.
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难熔高熵合金的从头预测微观机械性能
DOI：
10.1038/srep12334
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发表时间：
2015-07-22
影响因子：
4.6
通讯作者：
Vitos L
中科院分区：
文献类型：
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作者：
Li X;Tian F;Schönecker S;Zhao J;Vitos L
最近开发的由多种主要元素组成的高熵合金 (HEA) 代表了冶金的一个新领域，并在广泛的应用中表现出了吸引人的特性。利用初始合金理论，我们揭示了合金化对四种基于 Zr、V、Ti、Nb 和 Hf 的体心立方 (bcc) 耐火 HEA 的弹性性能和 [001] 方向理想拉伸强度 (ITS) 的影响。我们发现这些 HEA 显示出高弹性各向异性和大的正柯西压力，表明具有良好的外延性。从ZrNbHf开始，发现ITS随着等摩尔Ti的添加而降低。另一方面，如果ZrNbHf中同时添加Ti和V，则ITS提高约42%。如果用 Ti 和 V 代替 Hf，则更令人着迷的效果是 ITS 增加约 170%。 ITS 上的合金化效应可以通过 d 带填充来解释。在单轴拉伸下的失效模式方面发现了固有的脆性到延性的转变。这些研究表明，通过控制第四族元素与第五族元素的比例，可以实现具有高理想强度的本质延展性 HEA。
Recently developed high-entropy alloys (HEAs) consisting of multiple principal elements represent a new field of metallurgy and have demonstrated appealing properties for a wide range of applications. Usingab initioalloy theory, we reveal the alloying effect on the elastic properties and the ideal tensile strength (ITS) in the [001] direction of four body-centered cubic (bcc) refractory HEAs based on Zr, V, Ti, Nb and Hf. We find that these HEAs show high elastic anisotropy and large positive Cauchy pressure, suggesting good extrinsic ductility. Starting from ZrNbHf, it is found that the ITS decreases with equimolar Ti addition. On the other hand, if both Ti and V are added to ZrNbHf, the ITS is enhanced by about 42%. An even more captivating effect is the ITS increase by about 170%, if Ti and V are substituted for Hf. The alloying effect on the ITS is explained by thed-band filling. An intrinsic brittle-to-ductile transition is found in terms of the failure mode under uniaxial tension. These investigations suggest that intrinsically ductile HEAs with high ideal strength can be achieved by controlling the proportion of group four elements to group five elements.