In situ synthesized 3D network structure TC4 metal matrix composites reinforced by the graphene via using laser additive manufacturing
Guonan Zhang, Naiwen Zuo, Yuxi Gao, Jingshun Liu, Yongquan Han, Huaming Wang
Abstract
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.