In situ synthesized 3D network structure TC4 metal matrix composites reinforced by the graphene via using laser additive manufacturing

Due to high flexibility, non-mold short working cycle, free-from parts structure, and material constraints, laser additive manufacturing (LAM) has been applied to compose nanoparticle-reinforced metal matrix composites. In this work, cost-effective combined with high-performance 3D network graphene nanosheet (GNS) with TiC particles-reinforced Ti–6Al–4V (TC4) composites were conveniently prepared via the LAM process, leveraging the in situ Ti + C → TiC chemical reaction. This preparation method facilitated the formation of a highly uniform reinforcement phase network (GNS-TiC/Ti) distributed within the Ti–6Al–4V α/β matrix. The size of the GNS-TC4 grain decreased synchronously as the addition of GNS increased, primarily caused by the in situ TiC nanoparticles pinning effect along grain boundaries, which plays a limiting role in the process of grain growth. Mechanical result indicated that the incorporation of 1 wt% GNS resulted in 1.56 % increase in microhardness and 29.7 % increase in yield strength compared to the direct addition of TiC-reinforced TC4. The analysis of the alloy structure at the subsurface of the fracture revealed the uniform distribution of the situ-generated TiC particles in the alloy matrix, and no defects of the pores were observed around the particle. The reinforced strength of the GNS-TC4 is attributable primarily to shear-lag strengthening and thermal mismatch strengthening mechanism. This work furnishes new thoughts into the preparation of balanced-performance titanium matrix composites when combined with laser additive manufacturing technology.