Strength-plasticity synergy of deformed Ti2AlC particles in aluminum matrix composites via interlayer slip

In this study, we focus on clarifying the synergistic mechanism of strength and plasticity of deformed particles on aluminum matrix composites. Ti2AlC reinforcement was selected to prepare deformed particle reinforced composites with different contents by spark plasma sintering and hot extrusion process. The composite with preferred orientation and optimal addition of Ti2AlC particles demonstrates a tensile strength of 252 MPa with 15 % tensile strain, showing a good balance of strength and plasticity. The Kernel Average Misorientation (KAM) maps obtained by Electron Backscatter Diffraction (EBSD) analysis shows that high-angle misorientation is mainly distributed inside the Ti2AlC, indicating that the deformation is concentrated in the particles. With the increase of particle content, the geometrically necessary dislocation (GND) density estimated by the KAM values gradually increases, revealing that deformation of particles promotes dislocation strengthening. The deformed surface morphology reveals that the Ti2AlC particle is mainly deformed by interlayer sliding, and the texture of Ti2AlC has a close influence on the particle fracture behavior. In addition, the strengthening mechanisms of load transfer, grain refinement and dislocation are discussed for composites under different volume fractions to analyze the improvement of yield strength. The results demonstrate that dislocation strengthening caused by particle deformation dominates at low content, and the effect of grain refinement strengthening becomes equally significant at high content. The strength-plasticity synergistic effect of composites mainly makes full use of the deformation ability of Ti2AlC particles and promotes the synergistic effect of multiple strengthening mechanisms.