Fusion zone characterization of resistance spot welded maraging steels via selective laser melting
Fusion zone characterization of resistance spot welded maraging steels via selective laser melting
复制标题
通过选择性激光熔化对电阻点焊马氏体时效钢的熔合区进行表征
DOI：
10.1016/j.jmatprotec.2019.116253
复制
发表时间：
2019-11-01
影响因子：
6.3
通讯作者：
Zhang, Yansong
中科院分区：
文献类型：
--
作者：
Luo, Cheng;Zhang, Yansong
选择性激光熔化制备高性能马氏体时效钢在汽车应用中受到了极大的关注。研究了马氏体时效钢激光选区熔化电阻点焊接头的组织演变及其与力学性能的关系。马氏体时效钢点焊接头存在内熔合区、外熔合区、热影响区和母材四个区域。在定向凝固过程中，内熔合区为柱状枝晶组织，外熔合区为粗大的等轴晶组织，具有不同的晶向。晶粒细化和织构的存在会使内熔合区的硬度比外熔合区的硬度有所提高。此外，外熔合区的相对软化会使裂纹在熔合区萌生并沿板厚沿着扩展，导致部分界面失效。
High-performance maraging steels fabricated by selective laser melting has received a great deal of attention in automotive applications. This paper reports on the microstructure evolution of resistance spot welded maraging steels via selective laser melting and their relation to mechanical performance. Four regions of inner fusion zone, outer fusion zone, heat-affected zone and base metal are found in the spot welds of maraging steels. The inner fusion zone is observed in the form of column dendritic structure in directional solidification, whereas the outer fusion zone forms coarse equiaxial structure with various crystal orientations. Grain refinement and the existence of texture would increase the hardness in the inner fusion zone with comparison to the value of outer fusion zone. Moreover, the relative softened outer fusion zone would make the crack initial in the zone and propagate along the sheet thickness, which results in the occurrence of partial interfacial failure.