Performance evaluation of interfacial characteristics between cold metal transfer-wire arc additive manufactured SS308LSi and wrought SS304L with controlled and uncontrolled interlayer temperature

The present work investigates the mechanical behavior and microstructure evolution of the interface between the cold metal transfer (CMT)-wire arc additive manufactured (WAAM) SS308LSi and wrought SS304L via controlled interlayer temperature (CIT) of 100–120°C and uncontrolled interlayer temperature (UIT). The thermal cycles on the substrate were recorded using K-type thermocouples and correlated with the mechanical and microstructure properties of deposited walls. Microstructure analysis of the interface cross-section revealed a defect-free interfacial bond with a columnar solidification structure with slightly coarser grains under UIT deposition compared to CIT deposition. The microhardness of wrought SS304L is in the range of 196 ± 9 HV, while that of UIT and CIT deposited 308LSi is 178.4 ± 7.02 HV and 183.4 ± 6 HV, respectively, with no aberrant hardness values at the interface. Tensile tests were performed on the wrought SS304L and WAAM SS308LSi transverse to their interface. The results revealed that interface strength is higher than that of WAAM deposits and failed with average ultimate tensile strengths of 589.1 and 580.9 MPa under CIT and UIT depositions, respectively. This work reveals that CMT-WAAM can produce high-quality interfacial bonding between WAAM SS308LSi and wrought SS304L.