This study investigates the fabrication of spatially-variable heterostructured CoCrFeMnNi high entropy alloy (HEA) using pulsed laser processing. Two distinct fabrication approaches, involving single-(SP) and double-sided (DP) laser passes, were employed. Microstructural characterization through electron backscatter diffraction revealed significant differences. SP-HEA exhibited a spatially heterogeneous microstructure with coarse columnar grains, while DP-HEA displayed a sandwich-like structure with fine equiaxed recrystallized grains. Microhardness mapping demonstrated a gradient trend in SP-HEA, with the fusion zone exhibiting the lowest hardness and the base material the highest. In contrast, DP-HEA displayed an overall soft-hard-soft structure. Tensile testing revealed distinct mechanical responses, with DP-HEA exhibiting higher strength and ductility compared to SP-HEA. The improved performance of DP-HEA was attributed to a more uniform distribution of heterogeneity, minimizing mechanical interactions between soft and hard domains. Moreover, corrosion resistance was assessed, showing that DP-HEA outperformed SP-HEA and non-processed material, suggesting superior stability in corrosive environments. These findings highlight the profound influence of fabrication parameters on the microstructure and mechanical properties of spatially-variable heterostructured HEAs. The study contributes valuable insights for material design and applications based on CoCrFeMnNi high entropy alloys.

中文翻译：

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激光加工制备空间可变异质结构CoCrFeMnNi高熵合金

本研究研究了使用脉冲激光加工制造空间可变异质结构 CoCrFeMnNi 高熵合金 (HEA)。采用了两种不同的制造方法，包括单面（SP）和双面（DP）激光通道。通过电子背散射衍射的微观结构表征揭示了显着差异。SP-HEA 表现出具有粗大柱状晶的空间异质微观结构，而 DP-HEA 表现出具有细等轴再结晶晶粒的三明治结构。显微硬度图显示 SP-HEA 呈梯度趋势，熔合区硬度最低，基材硬度最高。相比之下，DP-HEA 显示出整体的软-硬-软结构。拉伸测试显示出明显的机械响应，与 SP-HEA 相比，DP-HEA 表现出更高的强度和延展性。DP-HEA 性能的提高归因于异质性分布更加均匀，最大限度地减少了软域和硬域之间的机械相互作用。此外，对耐腐蚀性进行了评估，结果表明 DP-HEA 优于 SP-HEA 和未加工材料，表明在腐蚀环境中具有优异的稳定性。这些发现凸显了制造参数对空间可变异质结构 HEA 的微观结构和机械性能的深远影响。该研究为基于 CoCrFeMnNi 高熵合金的材料设计和应用提供了宝贵的见解。