Dissimilar laser welding of CrMnFeCoNi high entropy alloy and 316LN stainless steel for cryogenic application.

• Dissimilar laser welding of CrMnFeCoNi high entropy and 316N austenitic stainless steel was performed. • The ultimate strength of the welded joints is 510 MPa at room temperature and 820 MPa at 77 K, which can reach ∼90 % of the base materials at both room and cryogenic temperatures. • The dominant deformation mechanism was mainly twinning during the plastic deformation which accounting for the higher tensile strength, especially at cryogenic temperature. • The sound welded joints between CrMnFeCoNi high entropy and 316N austenitic stainless steel can be considered for cryogenic applications. The microstructure and mechanical properties of dissimilar laser beam welded joint between CrMnFeCoNi alloy and 316LN stainless steel was investigated. The results showed that the defect-free dissimilar joint was obtained by laser beam welding. The ultimate strength of the welded joints can reach ∼90% of the base materials at both room and cryogenic temperatures. The deformation substructure mainly consisted of planar dislocation, the stacking faults and the dissociation of stacking faults into nanotwins. The volume fraction of the nanotwins was increasing at cryogenic temperature. The hardness fluctuates greatly in welded joint and the lowest hardness was located at fusion zone near the fusion line. The fracture of the welded joint was located at the fusion zone in consistence with the lowest hardness area. It is mainly attributed to the coarse grain and stress concentration at this area. [Display omitted] [ABSTRACT FROM AUTHOR]