Study of Structure Formation and Mechanical Properties in an Al-Cu-Ce Alloy with Additives of SiC, TiC and TiB2 in the Process of Laser Exposure

This study investigates the fabrication of TiC-SiC-TiB2-reinforced aluminum matrix composites via laser melting, examining the synergistic effects of powder pre-treatment and laser processing parameters on microstructural evolution and mechanical properties. Mechanical alloying of precursor powders for 120 min optimized ceramic particle refinement and reinforcement homogeneity, enhancing density and hardness while providing an ideal substrate for subsequent laser processing. Laser melting experiments conducted at 610 W, utilizing substrate temperatures of both ambient (room temperature) and 400 °C, revealed that pre-heating to 400 °C extended melt duration and enhanced microstructural uniformity. This resulted in coarser primary silicon particles (~10 μm), contrasting with the inhomogeneous structure formed at room temperature, which contained finer silicon particles (~3 μm). Higher laser power mitigated TiB2 segregation, enabling reactive participation in TiC/Si formation and diffusion-driven spheroidization. Apparently, decomposition of SiC released silicon into the matrix and carbon for the in-situ formation of TiC, MAX phases (Ti3SiC2), and Al3Ti. Microhardness increased with laser power, peaking at 380 HV0.1 after laser melting at 370 W.