Mao Dongxin, Xie Yuming, Meng Xiangchen, Ma Xiaotian, Zhang Zeyu, Sun Xiuwen, Wan Long, Volodymyr Korzhyk, Huang Yongxian
State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin 150001, China.
Zhengzhou Research Institute, Harbin Institute of Technology, Zhengzhou 450000, China.
Mater Horiz. 2024 Jul 15;11(14):3408-3419. doi: 10.1039/d4mh00139g.
In the quest for excellent light-structural materials that can withstand mechanical extremes for advanced applications, design and control of microstructures beyond current material design strategies have become paramount. Herein, we design a coherent shell at incoherent precipitates in the 2195 aluminum alloy with multi-step metastable phase transitions. A high local strain rate a neoteric deformation-driven metallurgy method facilitated the diffusion of Li. The original T (AlCuLi) phases were transformed into coherent-shell (Li-rich) irregular-coated incoherent-core (AlCu) precipitates. The ultimate tensile strength and elongation reached 620 ± 18 MPa and 22.3 ± 2.2%, exhibiting excellent strength-ductility synergy. Grain boundaries, dislocation, solid solution atoms, and precipitates all contributed to the yield strength of the materials, among which precipitates occupied a dominant position, contributing approximately 56.07%. A new "incoherent-coherent interact" strain-hardening mechanism was also clarified, which was believed to be promoted in other heat-treatable alloy systems, especially with multi-step metastable phase transitions.
在寻求能够承受极端机械条件以用于先进应用的优异轻质结构材料的过程中，超越当前材料设计策略的微观结构设计与控制已变得至关重要。在此，我们通过多步亚稳相变在2195铝合金的非共格析出物处设计了一个共格壳层。高局部应变速率——一种新型的变形驱动冶金方法促进了锂的扩散。原始的T（AlCuLi）相转变为具有共格壳层（富锂）的不规则包覆非共格核心（AlCu）析出物。极限抗拉强度和伸长率分别达到620±18MPa和22.3±2.2%，展现出优异的强度 - 延展性协同效应。晶界、位错、固溶原子和析出物均对材料的屈服强度有贡献，其中析出物占据主导地位，贡献约56.07%。还阐明了一种新的“非共格 - 共格相互作用”应变硬化机制，据信该机制在其他可热处理合金体系中也会得到促进，尤其是在具有多步亚稳相变的体系中。
