Preparation and mechanical behavior of silver-coated graphene reinforced low modulus titanium matrix composites by selective laser melting

QS Xie and W Liu and XP Yan and H Zheng and ZH Li and PK Bai and LZ Ren, MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING, 926, 147944 (2025).

DOI: 10.1016/j.msea.2025.147944

Graphene nanosheets have become the most attractive carbonaceous material reinforcement in metal matrix composites due to its unique structure and excellent properties. However, the strong van der Waals forces between graphene nanosheets are easy to cause agglomeration and uneven distribution of reinforcement within the matrix. This work has utilized the chemical plating method to produce silver-coated graphene nanosheets (Ag@GNSs), then the Ti-13Nb-13Zr (TC26) alloys, GNSs/TC26 and Ag@GNSs/TC26 composites were fabricated respectively by the selective laser melting (SLM) technique. The effects of coating process on the powder characteristics and phase structure were studied, and the mechanical properties of SLM-ed composites were investigated to explore the strengthening mechanism of Ag@GNSs. The results showed that the addition of GNSs and Ag@GNSs has led to the distribution of in-situ generated granular TiC particles along the grain boundaries with decrease of grain size, which might bring about the decrease of texture strength, and the increase of recrystallized grains and dislocation density. The Ag@GNSs/TC26 composite demonstrated the maximum 0.2 % yield strength of 832.60 MPa and ultimate tensile strength of 986.25 MPa, while maintaining a higher elongation of 7.43 %. By simulating the tensile process of perfect lattice Ti and TiC/Ti composites with LAMMPs, it is confirmed that the formation of TiC in Ag@GNSs/TC26 composites have brought about the increase of tensile strength and decrease of elongation. Based on the strengthening mechanism, it is found that CTE and LT cooperative strengthening were the main reinforcements of GNSs/TC26 and Ag@GNSs/TC26 composites, which accounted for 77.06 % and 82.16 % of the total strength. Meanwhile, the contribution of fine grain strengthening and carbon solid solution strengthening was limited.

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