Novel NiAl-strengthened high entropy alloys with balanced tensile strength and ductility
Novel NiAl-strengthened high entropy alloys with balanced tensile strength and ductility
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DOI：
10.1016/j.msea.2018.11.055
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发表时间：
2019-01
期刊：
影响因子：
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通讯作者：
H. Diao;D. Ma;R. Feng;Tingkun Liu;Chao Pu;Chuan Zhang;W. Guo;J. Poplawsky;Yanfei Gao
中科院分区：
文献类型：
--
作者：
H. Diao;D. Ma;R. Feng;Tingkun Liu;Chao Pu;Chuan Zhang;W. Guo;J. Poplawsky;Yanfei Gao
单相、面心立方（FCC）Al 0.3CoCrFeNi高熵合金通常具有低屈服强度。在此，已经开发了沉淀强化的Al 0.3CoCrFeNi，其表现出增强的屈服强度，同时保持良好的延展性，这归因于在FCC基体的晶粒内包括精细分布的针状B2相和沿晶界沿着的粒状σ相的新颖显微组织。这样的微观结构是通过两步热处理的铸态Al0.3CoCrFeNi，其参数通过集成基于CALPHAD的热力学计算与原子探针断层扫描的微观结构表征确定。原位中子衍射，结合晶体塑性有限元模拟，揭示了由于组成相之间的负荷分配的强化效果。这一工作对于理解多主成分合金的相稳定性和变形机制具有重要意义，并为利用相关技术开发复杂合金中的新型微观结构铺平了道路。
A single phase, face-centered-cubic (FCC) Al0.3CoCrFeNi high entropy alloy usually has low yield strength. Here, a precipitate-strengthened Al0.3CoCrFeNi has been developed, exhibiting enhanced yield strength while retaining good ductility, which is attributed to a novel microstructure comprising a finely distributed, needle-like B2 phase within the grains of the FCC matrix and a granular σ phase along the grain boundaries. Such a microstructure was obtained by a two-step heat treatment of an as-cast Al0.3CoCrFeNi, whose parameters were determined by integrating CALPHAD-based thermodynamic calculations with microstructural characterization by atom probe tomography. In situ neutron diffraction, in conjunction with crystal-plasticity finite-element simulations, has revealed the strengthening effect owing to the load partitioning between the constituent phases. This work has important implications for understanding phase stability and deformation mechanisms in multi-principal component alloys, and paves the way for developing novel microstructures in complex alloys using correlative techniques.