Microstructure and mechanical properties of M40/AZ91 composites fabricated by pressure infiltration method

The M40 carbon fibers reinforced magnesium matrix composites were fabricated by pressure infiltration method. The interfacial reactions and mechanical properties of the composites were optimized by adjusting the preheating temperatures of the preform (PRT) and the casting temperatures of the melting (CAT). The lower preheating temperatures of preform resulted in casting defects at the interface between carbon fibers and magnesium matrix and making composites rapidly to be failed in a brittle fracture mode. In addition, the higher casting temperatures of melting would result in excessive interfacial reactions at the interface, which would weaken the reinforcement effect of the carbon fibers. When the preheating temperature of the preform was 550 °C and the casting temperature of melting was 760 °C, the moderate interfacial reactions occurred at the interface and the bending strength of the composites reached its maximum value of 1793 MPa.