Fabrication and mechanical characterization of Al6061/Mg/TiB2 hybrid metal matrix composites

Abstract

This work explores the synthesis and thorough characterisation of Al6061-based hybrid metal matrix composites made by stir casting Al6061 alloy with 1.5 wt% Mg as the matrix material and reinforced with different TiB 2 contents (3–12 wt%). Microstructural analysis using SEM and EDS confirms the relatively uniform distribution of reinforcements at lower TiB 2 loadings, while higher contents promote particle clustering and agglomeration. XRD analysis verifies phase stability of the Al6061 matrix and the successful in-situ formation of TiB 2 without undesirable secondary phases. Mechanical evaluation reveals significant enhancements in microhardness, tensile strength, and impact toughness up to an optimal reinforcement level of 9 wt% TiB 2 . Beyond this threshold, mechanical performance deteriorates due to defect formation associated with particle agglomeration. A typical strength–ductility trade-off is observed, with increasing TiB 2 content leading to reduced elongation and fracture resistance. However, intermediate reinforcement levels achieve a balanced combination of strength and toughness through mechanisms such as effective load transfer and crack bridging. The findings underscore the critical influence of particle dispersion and interfacial bonding in tailoring the mechanical performance of HMMCs for advanced structural applications.