Additive manufacturing of compositionally gradient metal-ceramic structures: Stainless steel to vanadium carbide

Abstract

Processing of hard, refractory ceramic coatings in a metal matrix is challenging due to various factors including delamination or cracking due to large material property differences at the interphase, and non-uniform distribution due to improper mixing. These issues can be reduced or even eliminated if the coating had a gradual change in material properties from the surface to the inside. Additive manufacturing is now being looked at to accomplish compositional control beyond the ability to produce net shape parts for repair as well as adding functionality. In this study, laser engineered net shaping (LENS™) was used to manufacture compositionally gradient structures of vanadium carbide (VC) and stainless steel 304 (SS304). Compositions ranging from 5 to 100wt% of VC were mixed with SS304. The internal stress from the carbides significantly increased the hardness and wear resistance of the coatings. The 100%VC outer layer increased the hardness by 1450HV and lowered the wear rate by 95% compared to SS304 substrate.