Strong and ductile refractory high-entropy alloys with super formability
Strong and ductile refractory high-entropy alloys with super formability
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DOI：
10.1016/j.actamat.2022.118602
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发表时间：
2023-02
期刊：
影响因子：
9.4
通讯作者：
Cheng Zhang;Haoren Wang;Xinyi Wang;Yuanbo T. Tang;Qin Yu;Chaoyi Zhu;Mingjie Xu;Shiteng Zhao;Rui Kou;Xin Wang;B. E. MacDonald;R. Reed;K. Vecchio;P. Cao;T. Rupert;E. Lavernia
中科院分区：
文献类型：
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作者：
Cheng Zhang;Haoren Wang;Xinyi Wang;Yuanbo T. Tang;Qin Yu;Chaoyi Zhu;Mingjie Xu;Shiteng Zhao;Rui Kou;Xin Wang;B. E. MacDonald;R. Reed;K. Vecchio;P. Cao;T. Rupert;E. Lavernia
耐火高熵合金（RHEA）被认为是目前使用高温合金的高温结构应用的有前途的候选材料。然而，对于大多数报道的 RHEA 来说，其较差的延展性和可忽略不计的室温冷加工性阻碍了它们的使用。在此，我们报告了一种新型非等原子 NbTaTi 基 RHEA，无需表面处理和/或中间退火，其冷轧强度可比铸态减少 90% 以上。高密度位错和变形孪晶的激活以及高扩散率路径促进了这种优异的冷加工性，使得这些 RHEA 可以在较低的退火温度下在更短的时间内变得均匀。此外，我们报告说，RHEA 在高温下保持高强度，并在低温条件下表现出相当大的延展性，避免了传统的强度-延展性权衡。此类超可成形 RHEA 提供了一种新颖的设计途径，通过节能省时的方法来制造高温结构材料。
Refractory high-entropy alloys (RHEAs) are considered promising candidate materials for high-temperature structural applications that currently use superalloys. However, for most of the reported RHEAs, their poor ductility and negligible cold-workability at room temperature have hindered their use. Here, we report a new class of non-equiatomic NbTaTi-based RHEAs that can be cold-rolled to a reduction of over 90% from the as-cast state without surface treatment and/or intermediate annealing. This excellent cold-workability is facilitated by activation of a high-density of dislocations and deformation twins as well as by high diffusivity paths, such that these RHEAs can be rendered homogeneous at lower annealing temperatures for much shorter time durations. In addition, we report that the RHEAs retain their high strength at elevated temperatures and exhibit considerable ductility at cryogenic conditions, evading the traditional strength–ductility trade-off. This class of super-formable RHEAs provides a novel design pathway to fabricate high-temperature structural materials via an energy- and time-saving method.