Improving the ductility in laser welded joints of CoCrFeMnNi high entropy alloy to 316 stainless steel

Dissimilar joining involving high entropy alloys is currently being explored to evaluate the suitability of these novel advanced engineering materials in structural applications. Recently, joining of a CoCrFeMnNi high entropy alloy to 316 stainless steel was successfully attempted. However, the joint ductility was lim-ited by the lack of deformation experienced by the cold-rolled CoCrFeMnNi base material during tensile loading. In this work, it is shown that by simply changing the base material condition, from cold-rolled to annealed, it is possible to significantly improve the joint fracture strain from 5 to 10 %, while preserv-ing the strength at 450 MPa. Using electron microscopy, high energy synchrotron X-ray diffraction and mechanical testing aided by digital image correlation, the microstructure evolution across the welded joint is assessed and correlated to its mechanical performance. Moreover, thermodynamic calculations considering the compositional changes across the fusion zone were used to predict the microstructure evolution of this region.(c) 2022 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

This study investigates the improvement of joint performance between high entropy alloys and stainless steel by changing the base material condition. The microstructure evolution and mechanical performance of the welded joint are evaluated, and the composition changes across the fusion zone are considered to predict the microstructure evolution. The results provide insights into the mechanism for improving joint performance.