Effect of hard plate rolling on microstructure and mechanical properties of Mg-9Al-1Zn-based composites reinforced with Ti-6Al-4V particles

In this work, the TC4/AZ91 composites were fabricated through spark plasma sintering (SPS) followed by hard plate rolling (HPR) of a novel processing technology. The microstructure evolution and mechanical properties of the magnesium (Mg) matrix composites (MMCs) were investigated. The results illustrated that there were no other precipitates in TC4/AZ91 composites except for α-Ti and Mg 17 Al 12 phases. The grains were refined significantly and TC4 particles occurred plastic deformation after a single pass via HPR, and the grain refinement of the TC4/AZ91 composites after HPR was attributed to TC4-induced particle-stimulated nucleation (PSN) mechanism and the pinning effect of fine Mg 17 Al 12 phases. The deformable TC4 particles were beneficial to alleviate the stress concentration around them, resulting in dynamic recrystallization grain size around them being slightly smaller than relatively far away. Among them, the TC4/AZ91 composite with a thickness reduction of 70% by HPR exhibited favorable comprehensive mechanical properties: The yield strength (YS), ultimate tensile strength (UTS) and elongation (EL) were 206 Mpa, 349 Mpa and 7.9%, respectively. The superior mechanical properties were primarily ascribed to three aspects: (I) grain refinement, (II) the good interfacial bonding between Mg matrix and TC4 particles, and (III) the deformability of TC4 particles.