Laser engineered net shaping of graphene oxide reinforced titanium: Effects of reinforcement and laser power

Titanium is widely used in many industry areas (such as automotive industry, aerospace industry, and medical industry) due to its superior properties of low density, high strength to weight ratio, strong corrosion-resistance, etc. However, commercial pure titanium (CP-Ti) parts still have some disadvantages (such as relatively low hardness, and wear resistance) which limit their further applications. In order to reduce these disadvantages, some reinforcement materials (such as ceramics and nanomaterials) are involved to fabricate titanium-based parts Compared with ceramics, low content of nanomaterials could significantly improve the mechanical properties and reduce disadvantages of ceramics (such as poor wettability and low interfacial bonding between reinforcement materials and Ti). Graphene oxide (GO) is a preferable candidate of nanomaterial due to its excellent mechanical properties and low density. The GO reinforced Ti parts have been fabricated by the selective laser sintering (SLS) process. Laser additive manufacturing (LAM) process includes directed energy deposition method and powder bed fusion method. Compared with powder bed fusion method (such as the SLS and selective laser melting (SLM)), directed energy deposition method (e.g. laser engineered net shaping (LENS)) has advantages of parts repairing and gradient parts fabrication capabilities. There are no studies on the fabrication of GO-Ti parts by LENS process. In this study, GO-Ti parts are fabricated by the LENS process. The effects of GO and laser power on fabricating defects of porosity, microstructure, and mechanical properties (including microhardness, elastic modulus, wear rate) were studied, for the first time.