Mechanical damage behavior of metal matrix composites with the arbitrary morphology of particles

Abstract

Metal matrix composites have significant applications in the engineering field. During service, the fracture is one of the most typical failure modes. In this study, the digital image-based technique (DIT) combined with a micro-scale damage cohesive finite element model (CFEM) was employed to reconstruct the microstructures of metal matrix composites with the arbitrary morphology of particles. The cohesive finite element in this model can predict the process of crack initiation and propagation spontaneously, and the effectiveness of the model was verified by the in-situ tensile tests of the compacted graphite iron (CGI) sample. We found that the morphology and distribution of the graphite particles play important roles in crack initiation and propagation under tensile and compressive loadings. The relationship between the graphite particle size and yield strength was established, and an optimal graphite particle size was found for the maximum yield strength, which is different from the previous results. The relationship between microstructures and tensile properties of CGI could contribute to the design and development of metal matrix composites with optimal mechanical properties.

Keywords

• Metal matrix composites
• Damage cohesive finite element model
• Graphite particle
• Crack initiation