Microstructure, properties and strengthening mechanism of N-SiCp/ AM60B composites

Magnesium matrix composites are widely used in aerospace and other fields due to their excellent mechanical and physical properties. In this study, monolithic AM60B alloy and AM60B matrix composites reinforced with three different weight fractions (1.0 %,2 %,3.0 % wt%) of nano-particulates SiC (N-SiCp) were synthesized by reciprocating extrusion and forward extrusion. The effect of the weight fractions of reinforcement on the mechanical properties, and corrosion behavior were investigated. The findings reveal that the N-SiCp/AM60B composite demonstrates substantially higher yield strength compared to the base alloy, with the 2 % N-SiCp/ AM60B composite achieving the highest tensile strength and yield strength of 349 MPa and 261 MPa, respectively. The strength increase is primarily attributed to grain refinement. However, when the N-SiCp content reaches 3 %, the formation of large N-SiCp clusters leads to a significant decline in the mechanical properties of the composite. Electrochemical analysis was employed to evaluate the corrosion behavior, revealing that the incorporation of N-SiCp reduces the self-corrosion potential (Ecorr) and polarization resistance (Rp) of the material. Both electrochemical polarization curves and impedance spectroscopy indicate that the addition of SiC reduces the corrosion resistance of the alloy. The primary reason for the increase in corrosion rate is that the introduction of N-SiCp alters the microstructure of the composite. Nevertheless, as the N-SiCp content increases, the corrosion resistance of N-SiCp/AM60B composites improves due to the increased surface area of SiC particles.