Deformation and damage of an Al/PTFE composite under uniaxial compression: An in situ synchrotron X-ray tomography study

The deformation and damage mechanisms of aluminum/polytetrafluoroethylene (Al/PTFE) composites under quasi-static compression are critical for aerospace, defense and structural applications, yet their mesoscale behavior remains insufficiently understood. This study combines in situ synchrotron X-ray micro computed tomography (CT) with CT-based finite element method (FEM) simulations to dynamically resolve the interplay between microstructure evolution and mechanical response. Real-time 3D imaging reveals negligible contributions of initial voids to bulk deformation, while catastrophic failure is governed by shear-induced interfacial debonding between Al particles and progressive void coalescence. Mesoscale FEM simulations quantify stress localization on Al particles, demonstrating its dependence on particle alignment relative to the loading direction. Damage initiates exclusively when adjacent particles deviate from the loading direction, underscoring the pivotal role of microstructural heterogeneity. These findings provide new insights into mesoscale structure–property relations in Al/PTFE composites, and the combined methodology of in situ CT experiments and CT image-based FEM simulations offers potential for advancing mechanistic studies of multiphase composites under complex mechanical conditions.