Exploring the mechanical, metallurgical, and fracture characteristics of hybrid-reinforced magnesium metal matrix composite synthesized via friction stir processing route

Abstract

Low-cost hybrid-reinforced magnesium metal matrix composite (HMMC) materials present a revolutionary category of materials achieved by combining two or more distinct reinforcing elements within the magnesium (Mg) matrix. The main focus of this research is to fabricate Mg-based HMMCs with exceptional mechanical and other characteristics by utilizing Mg substrate AZ61A as the base material. To achieve this, nano-titanium carbide (TiC), nano-silicon carbide (SiC), and fly ash (FA) were selected as hybrid reinforcements, and the friction stir processing technique was employed for their incorporation. The microstructural, thermal, mechanical, wear, and fracture properties of synthesized HMMCs were carefully examined using a conventional testing approach. The findings demonstrate that the grain size of the base AZ61A alloy was measured at 32 µm, whereas the AZ61A/FA/TiC/SiC composite exhibited a remarkable reduction to 3.5 µm. Notably, this reduction in grain size leads to simultaneous enhancement in mechanical properties. The microhardness, ultimate tensile strength, and ultimate compressive strength of the developed HMMC showed an impressive increase, measuring 2.09 times, 2.75 times, and 2.10 times higher, respectively, compared to their initial values of the base material. Moreover, a significant enhancement in wear resistance was also observed, attributed to the increased hardness and homogenous hybrid reinforcement dispersion into the HMMCs. In addition, it was evident that the synergistic combination of different reinforcement particulates in Mg-based alloy improves overall fracture resistance and catastrophic failure and mitigates crack propagation.