LM30-corundum aluminum matrix composites were fabricated via stir casting using controlled corundum particle size fractions of 1–32 μm, 50–75 μm, and 106–125 μm with reinforcement levels ranging from 5 to 20 wt%. Optical microscopy revealed significant primary silicon refinement from 54 μm in the LM30 alloy to 10 μm in the 20 F composite. Williamson-Hall analysis indicated a maximum dislocation density of 1.54 × 1015 m− 2 in fine-particle composites. The coefficient of thermal expansion decreased by approximately 50% compared to the base alloy. Elevated-temperature wear tests conducted between 50 and 300 °C under contact pressures of 0.2–1.8 MPa demonstrated a delayed mild-to-severe wear transition from 150 °C in LM30 alloy to 200–250 °C in reinforced composites. Fine-particle composites exhibited the lowest wear rate and coefficient of friction due to enhanced dislocation density, refined Si morphology, and improved mechanically mixed layer stability.
Mann et al. (2026) studied this question.