Wire and Laser Additive Manufacturing of Titanium/Steel Composites: Effect of Copper Interlayer on Microstructure and Mechanical Properties of Ti-Cu-Fe Interface Region

Additive manufacturing (AM) is a suitable technology for preparing multi-metallic materials due to the characteristic of layer by layer forming. In this work, the wire and laser additive manufacturing (WLAM) process with the addition of S201 Cu (laser power of 1300 W) is selected for fabricating the 309L (laser power of 1700 W)/TC4 (laser power of 1300 W) composites under the scanning speed of 400 mm/min. The results show no obvious defects in the AMed TC4/309L composites. The investigation on the microstructure of the Fe/Cu and Cu/Ti interfaces finds that the latter is the key interface because it contains brittle phases, which make the maximum hardness of Cu/Ti interface reach 533.5 HV. In the micro-region tensile test, the cracks appeared in the brittle phase region and expanded around the interface during the tensile process. The interfacial bonding strength is 158.4 MPa, showing the characteristics of brittle fracture.