Novel reduced-activation TiVCrFe based high entropy alloys
Novel reduced-activation TiVCrFe based high entropy alloys
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DOI：
10.1016/j.jallcom.2020.157399
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发表时间：
2021-01-25
影响因子：
6.2
通讯作者：
Pickering, E. J.
中科院分区：
文献类型：
--
作者：
Carruthers, A. W.;Li, B. S.;Pickering, E. J.
下一代核反应堆内部的条件可能很极端。将需要高性能材料，并且在开发新型改良合金方面仍有很大空间。高熵合金（HEAs）是潜在的候选材料，而且这类合金可能需要以倾向于形成体心立方结构的低活化元素为基础。虽然已经有许多研究评估了CALPHAD数据库预测面心立方高熵合金中形成相的能力，但它们对研究较少的体系的适用性尚不明确。在此，制备了两种低活化高熵合金：TiVCrMnFe和Si0.1TiVCr0.5Fe，并对它们的微观结构进行了评估，且与CALPHAD预测结果进行了比较。两种合金铸造后的微观结构都包含C14拉弗斯相和B2相，在1200℃保温后包含C14拉弗斯相和体心立方固溶体（A2）相，且在每种情况下都发现两种组成相的比例都很高。通过实验发现，两种合金中的拉弗斯相都是Fe、V、Cr和Ti的四元金属间化合物，其中Fe、V和Cr可能在Fe位点上无序排列。将这些观察结果与使用四个CALPHAD数据库所做的预测进行了比较。不同数据库之间预测的准确性差异显著。发现那些没有考虑相的五元性质的数据库往往严重低估了拉弗斯相。从TiVCrMnFe中去除Ti得到了等原子的VCrMnFe合金，该合金在1200℃时形成单一的体心立方相。（C）2020作者。由爱思唯尔B.V.出版
The conditions inside next-generation nuclear reactors are likely to be extreme. High-performance materials will be required, and there is still great scope for developing new and improved alloys. High-entropy alloys (HEAs) are potential candidates, and it is likely that such alloys will need to be based around low-activation elements that tend to form body-centred cubic structures. Whilst there have been a number of investigations assessing the capability of CALPHAD databases to predict the phases formed in face-centred cubic HEAs, their applicability to less studied systems is not well known. Here, two low-activation HEAs are produced; TiVCrMnFe and Si0.1TiVCr0.5Fe, and their microstructures assessed and compared to CALPHAD predictions. The microstructures of both alloys comprised a C14 Laves phase and a B2 phase following casting, and a C14 Laves phase and a BCC solid solution (A2) phase following holding at 1200 degrees C, with high proportions of both constituent phases found in each case. It was found experimentally that the Laves phases in both alloys were quaternary intermetallics of Fe, V, Cr and Ti, with Fe, V and Cr likely disordered across the Fe site. These observations were compared with predictions made using four CALPHAD databases. The accuracy of the predictions varied markedly between the databases. It was found that the Laves phase was underpredicted, often severely, by the databases that did not account for the quinary nature of phase. Removing Ti from TiVCrMnFe resulted in an equiatomic VCrMnFe alloy that formed a single BCC phase at 1200 degrees C. (C) 2020 The Authors. Published by Elsevier B.V.