Stress partitioning and strain localization in Al-SiC composites

KM Shao and C Luo and Y Cai and L Wang and BX Bie and K Li and YJ Deng and L Lu and SN Luo, INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES, 308, 110947 (2025).

DOI: 10.1016/j.ijmecsci.2025.110947

Al-SiC composites offer superior strength-to-weight ratios for aerospace and automotive applications, and it is valuable to understand stress partitioning and load transfer efficiency between the constituent phases. Here, we investigate stress partitioning and strain localization in Al-SiC composites subjected to uniaxial tension using multiscale approaches: molecular dynamics (MD) simulations, MD-based X-ray diffraction (XRD) simulations, and in situ synchrotron XRD experiments. The methodology of XRD-derived lattice strain analysis, stress calculation based on the generalized Hooke's law, and the stress partitioning model are quantitatively validated against direct MD simulations. The mismatch in stiffness and yield strength between the SiC reinforcement and the Al matrix, and consequently, deformation mechanisms, leads to stress transfer to the SiC reinforcement and strain localization into the Al matrix. MD reveals an appreciable stress gap between SiC and Al, and strain localizations in Al through stacking faults and grain boundary reconfiguration. In contrast, SiC accommodates deformation through particle rotation. The in situ synchrotron XRD experiments and the MD simulations demonstrate the load transfer efficiency of the SiC reinforcement across the atomic and meso scales, and the relation between constrained plasticity and stress partitioning.

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