Physical and mechanical characterization of dissimilar laser welded joints of AISI 316/Cu/SMA using fiber laser technology

The present study explores an experimental investigation of dissimilar welding of austenitic stainless steel (AISI 316) with nitinol (NiTi) plates by inserting copper (Cu) as an interlayer using a fiber laser system. The presence of copper influences controlling the formation of brittle intermetallic compounds forming compounds of copper with iron, titanium, and nickel. The weldments are examined to understand the physical and mechanical properties of the joints. A micrograph study of welded joints shows a crack-free surface and reveals the nature of solidification in the weld zone. The analysis of pores in the weldment indicates the presence of 1.89%, 2.26%, and 6.32% of pores in the weld zone area of three different weldment samples, 1, 2, and 3, respectively, and the obtained porosity percentage was quite satisfactory. The insertion of copper helps in attaining the welded joints bearing a tensile strength of 219.74 MPa. The failure of the welded joint shows a mixed nature of fracture. This study suggests that the presence of an interlayer during joining of dissimilar materials provides stable, crack-free, and less brittle joints as compared to joining of dissimilar materials without an interlayer. The author of the article agrees to the retraction of the article effective JULY 12, 2021.