Additive manufacturing of VCoNi medium-entropy alloy: microstructure evolution and mechanical properties
Additive manufacturing of VCoNi medium-entropy alloy: microstructure evolution and mechanical properties
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DOI：
10.1016/j.addma.2023.103522
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发表时间：
2023-03
影响因子：
11
通讯作者：
A. Amar;Mingliang Wang;Lingkun Zhang;Jin-Feng Li;Liufei Huang;Hongwei Yan;Yongan Zhang;
中科院分区：
文献类型：
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作者：
A. Amar;Mingliang Wang;Lingkun Zhang;Jin-Feng Li;Liufei Huang;Hongwei Yan;Yongan Zhang;
高熵和中熵合金作为一类新型的有前途的材料，因其具有传统合金所无法比拟的优异性能而受到广泛关注。由于固有的要求，HEAs和MEA的常规制造工艺受到显著的限制。另一方面，增材制造（AM）为生产大型和复杂形状的金属零件提供了一种新方法。研究了激光熔融沉积（LMD）法制备的VCoNi MEA样品的显微组织演变和力学性能。结果表明，单壁试样的整个横截面上都存在着胞状-柱状-等轴状的非均匀组织，这与LMD过程中成分过冷度的演变程度以及LMD过程的逐层沉积特性有关。试样的力学性能从上到下各不相同，主要是由于不同位置σ相含量的变化。在试样底部，拉伸伸长率和极限抗拉强度分别不低于10%和1.5GPa，而在试样顶部，这些参数分别为19.5%和≥ 1.2GPa。上述强度-塑性组合与最好的AM形成共晶高熵合金（EHEAs）相当，但比大多数报道的AM合金上级，这强烈地表明其在结构应用中的巨大潜力。
As a novel class of promising materials, high- and medium- entropy alloys (HEAs and MEAs) have attracted extensive attention due to their outstanding properties beyond those of conventional alloys. The conventional fabrication process of HEAs and MEAs suffers from significant limitations due to the intrinsic requirements. On the other hand, additive manufacturing (AM) has provided a new approach to producing large-scale and complex-shaped metallic parts. This study examined the microstructure evolution and mechanical properties of VCoNi MEA sample fabricated by laser melting deposition (LMD). The repeated cellular-columnar-equiaxed heterogeneous microstructure was found to occupy the whole cross-sectional area of single-wall sample, which was related to the degree of constitutional undercooling evolution and the repeated layer-by-layer deposition nature of the LMD process. The mechanical properties of samples varied from top to bottom, mainly due to the σ phase content variation in the different location. At the bottom of sample, tensile elongation and ultimate tensile strength were no less than 10% and 1.5 GPa, respectively, while at the top, these parameters were 19.5% and ≥ 1.2 GPa. The above strength-ductility combination was comparable to the best AM-forming eutectic high entropy alloys (EHEAs), but superior than most reported AM alloys, which strongly indicates its great potential in structural applications.