Effect of equal channel angular pressing on the mechanical properties of homogenized hybrid AZ61 magnesium composites

This study addressed the development and investigation of an AZ61 hybrid composite (HBC) fabricated by the stir casting method followed by equal channel angular pressing (ECAP). The HBC was reinforced using both Al₂O₃ and SiC nanoparticles. The microstructural examination showed that the introduced reinforcements broke down the round-like formed precipitates into needle-like shapes that enhanced the ductility. Furthermore, the grain size of the HBCs is highly reduced while increasing the number of ECAP passes due to dynamic recrystallization (DRX). The obtained mechanical properties showed that the optimal yield strength (YS), ultimate tensile strength (UTS), and elongation were observed in the AZ61 + 2%Al₂O₃ + 1%SiC hybrid composite after two passes of ECAP. The Hall[sbnd]Petch strengthening mechanism was primarily responsible for the improved mechanical properties of AZ61 HBC, jointly with the mutual contribution of several mechanisms, including the coefficient of thermal expansion, Orowan looping, and load transfer mechanisms.