材料科学
等轴晶
微观结构
极限抗拉强度
合金
高熵合金
延展性(地球科学)
晶界
复合材料
制作
选择性激光熔化
应变硬化指数
冶金
蠕动
病理
替代医学
医学
作者
Youxiang Chew,Guijun Bi,Zhiguang Zhu,Fern Lan Ng,Fei Weng,Shibo Liu,Mui Ling Sharon Nai,B.Y. Lee
标识
DOI:10.1016/j.msea.2018.12.005
摘要
The CoCrFeNiMn high entropy alloy (HEA) bulk alloy was successfully manufactured using laser aided additive manufacturing (LAAM). The microstructure and mechanical behaviors of the as-fabricated HEAs were investigated. The as-built HEAs exhibit directional solidification at regions close to the melt-pool boundaries, forming dendritic columnar grains and transiting to equiaxed grains further away from the boundaries. Compared with the conventionally cast HEAs, the CoCrFeNiMn fabricated using LAAM possesses significantly higher yield strength (518 MPa) and ultimate tensile strength (660 MPa). The strengthening effect is attributed to finer grains and could be explained quantitatively through grain boundary strengthening. The as-built HEA shows a simultaneous enhancement in yield strength and ductility with decreasing testing temperature. The improved low temperature tensile properties could be ascribed to the formation of deformation twins at low temperature, which results in a steady strain hardening behavior. This work demonstrates the potential of using LAAM technology to extend the application of HEAs with fabrication of larger and more complex parts with good mechanical properties.
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