Microstructure and scratch properties of GO/TC4 composites by selective laser melting

Graphene oxide (GO)-reinforced TC4 titanium alloy nanocomposites with different mass fractions were fabricated via selective laser melting (SLM). The microstructural evolution, interfacial reaction mechanisms, mechanical properties, and tribological behaviors of the composites were systematically investigated. GO was uniformly dispersed in TC4 powder through electrostatic adsorption self-assembly method, and SLM process parameters were optimized to obtain a dense structure. The experimental results demonstrate that the incorporation of GO (0.27-0.54 wt.%) promotes grain refinement, in-situ TiC precipitation, and interfacial metallurgical bonding, which effectively enhanced the hardness (up to 5.9 GPa), elastic modulus (164.9 GPa), and wear resistance (scratch width reduced to 20 μm) of the material. Transmission electron microscopy (TEM) and Raman spectroscopy analyses reveal the structural retention of GO during SLM and the formation mechanism of the TiC layer interfacial structure. The 0.27 wt.% GO/TC4 composite exhibits the optimal density, microstructural uniformity, and mechanical properties. This study provides a novel approach for the additive manufacturing and nano-reinforcement of high-performance titanium matrix composites, which can promate their engineering applications in the aerospace and biomedical fields.