Effect of iron powder content on microstructure and mechanical properties of Al₂O₃p/high manganese steel composites prepared by casting infiltration

Abstract

Al2O3p/high-manganese steel-matrix composites were successfully fabricated by gravity casting infiltration, with iron powder added in the preforms to adjust the Al2O3p fraction. The effects of the iron powder content (38, 48, and 55 wt.%) on the microstructures and mechanical properties of the composites were investigated. With the increase in the iron powder content in the preform, the Al2O3p fraction decreased (57–38 vol.%), while the hardness and compressive strength of the composite gradually increased. The highest compressive strength was 1000.3 MPa (55-wt.% iron powder). The highest work hardening rate (55-wt.% iron powder) well reflected the synergistic effect between the matrix and reinforcement to prevent dislocation movement. The water glass binder formed thick interface layers between Al2O3p and matrix, which transformed the Al2O3/metal interface bonding from mechanical bonding to metallurgical bonding. A too thick interface layer deteriorated the mechanical properties of the composites.