Influence of Particle Reinforcements on Texture Characteristics and Dislocation Activities of Mg–Zn Matrix Composites

Abstract

The introduction of ceramic particles into magnesium (Mg) alloys not only leads to a grain refinement effect but also influences their texture. However, dislocation activities within the Mg matrix resulting from these effects remain unclear. In this study, in-situ tensile testing in conjunction with synchrotron radiation techniques was utilized to investigate the microstructure, load partitioning, and dislocation density evolution of SiCp/Mg–5Zn and Mg–5Zn samples under different tensile strain conditions. It was found that more dislocation slip systems were involved in the SiCp/Mg–5Zn composite during tension deformation, whereas the Mg–5Zn alloy exhibited a higher capacity for dislocation accumulation. By an elasto-plastic self-consistent (EPSC) model and a full-field crystal plasticity finite element method (CPFEM) simulation, the pyramidal dislocation activity was identified after a 2% strain in the SiCp/Mg–5Zn composite. This was accompanied by the load transfer between α-Mg grains as well as regions with different SiCp volume fractions. Additionally, a novel texture formation mechanism of Mg matrix composites (MMCs) was proposed. The strengthening mechanisms induced by reinforcements were also quantified. This study provides theoretical insights for the design and application of advanced MMCs.

Keywords: Magnesium matrix composite, Dislocation behavior, Strengthening mechanism, Synchrotron radiation diffraction, Ductility