Ideal plasticity and shape memory of nanolamellar high-entropy alloys

作者：Chen, Shuai; Liu, Ping; Pei, Qingxiang; Yu, Zhi Gen; Aitken, Zachary H.; Li, Wanghui; Wu, Zhaoxuan; Banerjee, Rajarshi; Srolovitz, David J.^*; Liaw, Peter K.^*; Zhang, Yong-Wei^*

来源：Science Advances, 2023, 9(41): eadi5817.

DOI：10.1126/sciadv.adi5817

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• MICROSTRUCTURE
• MECHANISMS
• BEHAVIORS
• EVOLUTION
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• ALUMINUM
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Understanding the relationship among elemental compositions, nanolamellar microstructures, and mechanical properties enables the rational design of high-entropy alloys (HEAs). Here, we construct nanolamellar AlxCoCuFeNi HEAs with alternating high- and low-Al concentration layers and explore their mechanical properties using a combination of molecular dynamic simulation and density functional theory calculation. Our results show that the HEAs with nanolamellar structures exhibit ideal plastic behavior during uniaxial tensile loading, a feature not observed in homogeneous HEAs. This remarkable ideal plasticity is attributed to the unique deformation mechanisms of phase transformation coupled with dislocation nucleation and propagation in the high-Al concentration layers and the confinement and slip-blocking effect of the low-Al concentration layers. Unexpectedly, this ideal plasticity is fully reversible upon unloading, leading to a remarkable shape memory effect. Our work highlights the importance of nanolamellar structures in controlling the mechanical and functional properties of HEAs and presents a fascinating route for the design of HEAs for both functional and structural applications.

• 单位
  1; 上海大学