Joining of Copper and Stainless Steel 304L Using Direct Metal Deposition

In the current study, the feasibility of joining pure copper (Cu) and stainless steel 304L (SS304L) through direct metal deposition process was investigated by material characterization. Samples were analyzed in terms of microstructure, elemental distribution, and tensile testing. Direct depositing pure copper on SS304L shows copper was mechanically rather than metallurgical bonded with SS304L due to the poor dissolubility of iron in copper. Iron was diffused into copper with a diluted distance of 1.5 mm and above that, pure copper deposits were obtained. Columnar structure was observed at the copper region near the interface while the columnar grains became finer away from the interface and finally, equiaxed structure was observed. Tensile testing shows the yield strength and ultimate tensile strength of combined materials (copper and SS304L) are 123 MPa and 250 MPa and samples fractured at the copper section with a ductile fracture mechanism. The bi-material interface survived the tensile test. The yield strength and ultimate tensile strength of as-fabricated pure copper are 95.02 MPa and 186.66 MPa, respectively.