Ti6Al4V/SiC Metal Matrix Composites Additively Manufactured by Direct Laser Deposition

Nowadays, research on additive manufacturing of Ti6Al4V alloy is growing exponentially but there are just a few studies about additive manufacturing of metal matrix composite components. In this work, highly reinforced Ti6Al4V matrix composites with SiC particles have been additively manufactured by direct laser deposition (DLD). Ti6Al4V powder and SiC particles have been deposited layer by layer to form an additive thin wall structure. The geometry, microstructure, and microhardness of the samples are strongly influenced by the laser scanning speed used during de fabrication process. In addition, the effect of the SiC increment in reinforcement concentrations and the influence of SiC particle sizes in the microstructure have been evaluated, and the reaction mechanisms have been established. The percentage of reinforcement measured is lower than expected due to the reinforcement-matrix reactivity that results in partially dissolved SiC particles and the formation of a TiC and Si5Ti3 ring around them. The size and number of particles and reaction products depend on the initial size and percentage of reinforcement and the DLD scanning speed. The higher the size and percentage of SiC particles and reaction products in the matrix, the higher the hardening effect of the composite matrix.

Automated summary

In this study, highly reinforced Ti6Al4V matrix composites with SiC particles were successfully additively manufactured using direct laser deposition. The laser scanning speed was found to significantly affect the geometry, microstructure, and microhardness of the samples. The effect of SiC particle sizes and concentrations on the microstructure and the reaction mechanisms were evaluated. The results demonstrated that the reinforcement percentage was lower than expected due to the reactivity between the reinforcement and matrix, resulting in the formation of TiC and Si5Ti3. The findings have important implications for optimizing the additive manufacturing process and the final properties of composite materials.