Impact of quenching on the microstructure and mechanical properties of hybrid aluminum matrix composites (Al7075/SiC/TiB 2 )

The introduction of hybrid composites, which integrate multiple reinforcements, presents opportunities for further optimization. Hybrid aluminum matrix composites (AMCs) reinforced with silicon carbide (SiC) and titanium diboride (TiB₂) are particularly noteworthy due to the complementary advantages provided by these reinforcements. Microstructural analysis shows good bonding between the matrix and reinforcements; however, particle agglomeration and casting defects indicate a need for improved processing. While SiC dispersion enhances strength, the agglomeration of TiB₂ can be minimized through optimized processing, leading to a more homogeneous composite. Despite the anticipated increase in hardness from the reinforcements, the overall hardness decreased due to non-uniform dispersion and defects, negatively affecting wear resistance. Quenched composite had the lowest hardness (113.03 HV), likely due to residual stresses and interfacial issues. Such hybrid composites have been shown to be ideal for automotive brake systems, aerospace sliding interfaces, and structural wear-resistant components. The synergistic interaction between SiC and TiB₂ in the hybrid composite imparts superior wear resistance across a range of tribological conditions. This improvement is the result of microstructural hardening, efficient load sharing by ceramic particles, and stabilization via tribo-film and MML formation. Consequently, the SiC + TiB₂ hybrid composite is well suited for demanding environments involving high loads and sliding speeds, such as automotive and aerospace components.