Directly cast bulk eutectic and near-eutectic high entropy alloys with balanced strength and ductility in a wide temperature range
Directly cast bulk eutectic and near-eutectic high entropy alloys with balanced strength and ductility in a wide temperature range
复制标题
直接铸造块体共晶和近共晶高熵合金，在宽温度范围内具有均衡的强度和延展性
DOI：
10.1016/j.actamat.2016.11.016
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发表时间：
2017-02-01
期刊：
影响因子：
9.4
通讯作者：
Li, Tingju
中科院分区：
文献类型：
--
作者：
Lu, Yiping;Gao, Xuzhou;Li, Tingju
高熵合金（HEA）通常具有较弱的流动性和铸造性，并且成分不均匀性较大，这主要是因为它们含有高浓度的多种元素。因此，通过铸造大规模生产 HEA 受到限制。为了解决这个问题，共晶高熵合金 (EHEA) 的概念被提出，这为实现高质量工业规模 HEA 铸锭带来了一些希望，更重要的是，还获得了良好的机械性能。在实际的大规模铸造中，设计的 EHEA 的实际成分可能会偏离共晶成分。这种偏差对 EHEA 机械性能的影响对于工业生产很重要，这构成了当前工作的主题。在这里，我们制备了工业规模的接近共晶成分的 HEA 锭：亚共晶合金、共晶合金和过共晶合金。我们的结果表明，共晶成分的偏差不会显着影响 EHEA 的机械性能、铸造性，并且 EHEA 可以在宽的成分范围内以及在室温和低温下实现良好的机械性能。我们的研究结果表明，EHEA 同时具有高强度和高延展性，以及良好的流动性和可铸性，可以很容易地适应大规模工业生产。利用数字图像相关应变测量、原位同步加速器 X 射线衍射和透射电子显微镜等技术组合，对共晶和近共晶 HEA 的变形行为和微观结构演化进行了深入研究。首次报道了 EHEA 中的波状应变分布以及由此导致的颈缩延迟。 (C) 2016 Acta Materialia Inc. 由 Elsevier Ltd 出版。保留所有权利。
High entropy alloys (HEAs) usually possess weak liquidity and castability, and considerable compositional inhomogeneity, mainly because they contain multiple elements with high concentrations. As a result, large-scale production of HEAs by casting is limited. To address the issue, the concept of eutectic high entropy alloys (EHEAs) was proposed, which has led to some promise in achieving good quality industrial scale HEAs ingots, and more importantly also good mechanical properties. In the practical large-scale casting, the actual composition of designed EHEAs could potentially deviate from the eutectic composition. The influence of such deviation on mechanical properties of EHEAs is important for industrial production, which constitutes the topic of the current work. Here we prepared industrial-scale HEAs ingots near the eutectic composition: hypoeutectic alloy, eutectic alloy and hypereutectic alloy. Our results showed that the deviation from eutectic composition does not significantly affect the mechanical properties, castability and the good mechanical properties of EHEAs can be achieved in a wide compositional range, and at both room and cryogenic temperatures. Our results suggested that EHEAs with simultaneous high strength and high ductility, and good liquidity and castability can be readily adapted to large-scale industrial production. The deformation behavior and microstructure evolution of the eutectic and near-eutectic HEAs were thoroughly studied using a combination of techniques, including strain measurement by digital image correlation, in-situ synchrotron X-ray diffraction, and transmission electron microscopy. The wavy strain distribution and the therefore resulted delay of necking in EHEAs were reported for the first time. (C) 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.