Abstract Particle-reinforced aluminum matrix composites (PRAMCs) have great potential for application in aerospace, automotive, defense, and electronics due to their high specific strength and stiffness and good resistance to wear and corrosion. Achieving a superior trade-off between strength and ductility of PRAMCs necessitates an elaborate control of the microstructures, such as the size and distribution of particles, as well as the grain size, morphology, and texture of the matrix. Multiscale interaction between particles and the matrix’s microstructures is insufficiently understood due to the lag in high-resolution in-situ characterization. This work proposes a nonlocal physically-based crystal plasticity (CP) modeling approach to reveal the underlying micro-mechanisms of deformation and strengthening of a TiB2/Al-Zn-Mg-Cu composite with various microstructures. The results show that TiB2 particles interrupt the inherent deformation bands of particle-free matrix, induce additional intragranular deformation bands, and increase the number of intragranular slip systems. However, the particle-induced constraint and elastic-modulus mismatch intensify local strain/stress gradients and geometrically necessary dislocation (GND) accumulation, thereby exacerbating deformation inhomogeneity—an effect weakly correlated with particle size and grain size. In addition, particles exert a more pronounced influence on strain partitioning and GND distribution in coarse grains than in fine grains, while crystal orientation dominates stress partitioning. Compared with coarse particles, fine particles are superior in dispersing inherent strain concentrations within the matrix. The newly proposed model accurately captures these microstructural characteristics. This work provides novel insights into the microstructural design and strengthening mechanisms of PRAMCs to optimize high performance.
Wu et al. (Fri,) studied this question.