Enhanced mechanical and tribological properties of graphene nanoplates reinforced TC21 composites using spark plasma sintering

摘要

Graphene nanoplates (GNPs) reinforced TC21(Ti-6Al-2Sn-2Zr-3Mo-1Cr-2Nb-Si) (GNPs/TC21) composites were prepared by using spark plasma sintering (SPS). Microstructure, mechanical and tribological properties of the sintered GNPs/TC21 composites were systematically investigated. Microstructural observations demonstrated the formation of a special sandwich interface product is in situ TiC coated GNPs (TiC@GNPs) bands and TiC particles/plates in the microstructure of the sintered GNPs/TC21 composites. Results of mechanical testing indicated the excellent combination of strength and ductility of GNPs/TC21 composites owing to the dispersion strengthening effects of TiC particles/ plates as well as the load transfer between TiC@GNPs bands and TC21 matrix. GNPs/TC21 composite with 0.05 wt% GNPs addition exhibits the relatively excellent mechanical properties, i.e., yield strength of 1017.2 MPa, ultimate tensile strength of 1161.99 MPa and an elongation about 13.2%. Among them, the dispersion strengthening effect of TiC particles/plate was the dominant factor in 0.05 wt% GNPs /TC21 composites. When the GNPs content exceeds 0.1 wt%, TiC particles/plates and TiC@GNPs bands formed at grain boundaries. The excellent combination of strength and ductility of GNPs/TC21 composites owing to the dispersion strengthening effects of TiC particles/plates as well as the load transfer between TiC@GNPs bands and TC21 matrix. Furthermore, additions of GNPs have significantly improved the tribological properties of the sintered GNPs/TC21 composites. The wear loss of 0.05 wt% GNPs/TC21 composite decreased by 21% compared to that of the sintered TC21 alloy. The superior mechanical and tribological performances of GNPs/TC21 composites can be attributed to the unique strengthening effect and the lubricating efficiency of GNPs. This demonstrates that GNPs is an ideal filler for TC21 matrix composites, as the effective lubricant and favorable reinforcement.