Simulation-based microstructural analysis of thermal-mechanical fatigue behavior in SiCp/A356 composites for brake disc applications

This article presents a study on the fatigue damage behavior of SiCp/A356 composites in severe service conditions of brake discs. A representative volume element (RVE) was constructed using finite element modeling technology to simulate the microstructure characteristics of the composites which takes into account the fatigue characteristics of the matrix. The RVE was loaded with local strain components and temperature histories obtained through the simulation of the braking condition of an urban rail train. The study found that the alternating effect of compressive stress and residual tensile stress at the matrix near the interface, especially at the sharp corners of SiC particles, causes fatigue damage on the matrix. Brake temperature was identified as the main factor for thermal-mechanical fatigue damage of the brake disc, and the matrix near the high-temperature position of the friction surface was found to have the highest degree of damage and the fastest failure process. The fatigue microcrack morphology and micro-failure modes inside the RVE were in good agreement with those of SiCp/A356 brake disc, and the RVE was able to characterize the micro-fatigue failure behavior of the SiCp/A356 composites under service thermal-mechanical load. This article provides a novel approach for investigating the thermo-mechanical fatigue behavior of SiCp/A356 composites from macroscopic to microscopic.