Micromechanical behavior analysis of ZrB2/6061Al composites based on normalized Lode angle and stress triaxiality

Abstract

Particle-reinforced aluminum matrix composites (PRAMCs), such as ZrB2/6061Al, exhibit excellent mechanical properties and have diverse practical engineering applications. However, an effective numerical method for investigating their mechanical behavior is still lacking. Thus, this study aims to establish a series of 3D representative volume element (RVE) models and proposes a model that considers the ductile damage of the matrix and the traction separation behavior of the interface. A linear damage evolution law is introduced to characterize the stiffness degradation in the matrix elements. Symmetric boundary condition is applied to the RVE during loading simulations, and the accuracy of the predicted results is verified using experimental stress–strain curves. The results show that the addition of ZrB2 particles can effectively promote the load-bearing capacity of composites with reduced elongation; the fillet corner of the ZrB2 particles can alleviate the stress concentration and increase the elongation, but it decreases the load-bearing capacity. The normalized Lode angle and stress triaxiality are used to explain the cause of failure and reveal the effect of the fillet corner of the particle on the failure mode of the matrix. The proposed model can assess the mechanical behavior and damage evolution within composites and provide more accurate predictions of the mechanical properties of PRAMCs.

Keywords

• 3D RVE
• PRAMC
• ZrB2 nano-particles
• Mechanical behavior
• Ductile damage
• Normalized lode angle