Tensile fracture behavior of 316L stainless steel components fabricated with hybrid directed energy deposition and thermal milling manufacturing

The hybrid manufacturing technologies have provided the possibility of producing complex parts with good surface quality and complex structure that are difficult to manufacture using directed energy deposition (DED) or milling process. In order to keep the samples warm, avoid cooling shrinkage deformation and improve the metallurgical effect, thermal milling (TM) was carried immediately after DED. A serious of tensile specimens of 316L stainless steel were fabricated by hybrid DED and TM manufacturing, and the tensile properties were tested. The analysis of the macroscopic fracture and microstructure was combined to understand the fracture mechanism. There were many differences between the brittle fracture and ductile fracture including the fracture surface morphology and microstructures. Then, the tensile properties and hardness at different heights were compared. Finally, the effects of milling temperature on tool wear and residual stress were studied.