This study examines the thermal stress behavior of metal matrix composites (MMCs), with a focus on the influence of voids on thermal strain and the coefficient of thermal expansion (CTE). A finite element model (FEM) was developed using the software ABAQUS to simulate the thermal behavior of MMCs with ceramic particle reinforcement and to compare the models with and without voids using a two-dimensional periodic unit cell approach. The results showed that voids significantly increased thermal strain. At 473 K, the presence of voids increased the thermal strain by 8.50% in Model 1 and 2.27% in Model 2 compared with their corresponding void-free configurations. Additionally, the composite with voids exhibited a higher CTE, confirming that microstructural flaws impact thermal behavior. The thermal stress response of the composite with voids was about 15% higher than that of the control samples, underlining how voids affect the composite's thermal behavior. These results show the need to model material imperfections, including voids, accurately when determining the thermal performance of composites. The findings provide valuable insights for optimizing the design and reliability of MMCs, particularly in applications where thermal behavior is critical, such as in aerospace, automotive, and energy industries.

metal matrix composites, thermal stress, finite element analysis, coefficient of thermal expansion