Development, characterization, and mechanical properties of innovative in-situ high-entropy alloy reinforced magnesium matrix composites via ultrasonic-assisted processing

Cast magnesium-metal matrix (Mg-MMCs) composites are extensively exploited in aerospace and automotive manufacturing industries because of their excellent strength-to-weight ratio and superior damping characteristics. This research presents an innovative hybrid technique to produce high entropy alloy (HEA) reinforced magnesium matrix composites using an ultrasonic-assisted liquid state processing method. The results indicate that a more uniform distribution of HEA reinforcing phases within Mg matrix is achieved when composite is fabricated with 10 wt% reinforcement, compared to 5 wt% and 15 wt%. The in-situ reaction mechanisms between the HEA and Mg matrix were established both theoretically and experimentally. Homogenization heat treatment was conducted on both the base and composite materials, leading to the suspension of the beta-Mg17Al12 secondary phase into the primary alpha-Mg matrix. This heat treatment significantly improved mechanical properties, enhancing strength and ductility by 38 % and 136 % in base material and by 25 % and 145 % in composite, respectively. The mechanisms underlying these enhancements were elucidated through detailed analysis of fractographs and microstructures, highlighting the potential of homogenized in-situ composites for advanced engineering applications.