Characteristic strengthening mechanisms in body-centered cubic refractory high/medium entropy alloys
Characteristic strengthening mechanisms in body-centered cubic refractory high/medium entropy alloys
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DOI：
10.1016/j.scriptamat.2023.115442
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发表时间：
2023-07
影响因子：
6
通讯作者：
Qian He;S. Yoshida;N. Tsuji
中科院分区：
文献类型：
--
作者：
Qian He;S. Yoshida;N. Tsuji
本文报道了HfNbTaTi、HfNbTiZr、HfNbTi、HfTaTi和NbTiZr等原子耐火中熵合金的特征强化机制。通过高压扭转和随后的退火处理合金，以获得平均晶粒尺寸从几百纳米到几十微米的微观结构。通过室温拉伸试验评价了它们的力学性能。基于拉伸屈服强度数据获得RMEA的精确Hall-Petch关系。小斜率的Hall-Petch关系和弱晶粒细化强化被澄清归因于它们的低弹性模量。此外，RMEA中的摩擦应力高于常规BCC金属和合金。通过比较实验数据和理论模型，认为严重的晶格畸变和刃位错弹性场的相互作用是导致室温下RMEA高摩擦应力的主要原因。
The present work reports characteristic strengthening mechanisms of HfNbTaTi, HfNbTiZr, HfNbTi, HfTaTi, and NbTiZr equi-atomic refractory medium entropy alloys (RMEAs). The alloys were processed by high-pressure torsion and subsequent annealing to obtain microstructures with average grain sizes ranging from several hundred nanometers to several tens of micrometers. Their mechanical properties were evaluated by tensile tests at room temperature. Precise Hall–Petch relationships of the RMEAs were acquired based on the tensile yield strength data. Small slopes of the Hall–Petch relationships and weak grain refinement strengthening were clarified to be attributed to their low elastic modulus. In addition, the friction stresses in the RMEAs were higher than those of conventional BCC metals and alloys. By comparing the experimental data and a theoretical model, it was suggested that interaction between severe lattice distortion and elastic field of edge dislocations can largely contribute to the high friction stress of the RMEAs at room temperature.