Simulated Mechanical Properties of NbC-Fe Composite Material under Tensile Load

With the continuous development of composite materials for various application fields, the demand for their performance has increased substantially. Particle-reinforced composites are very promising owing to the unique comprehensive properties. However, the effects of NbC particles on the mechanical characteristics of steel matrix composites are still not fully clear. In this paper, a finite element model was established based on the real microstructure of NbC-Fe composites. The particle shape and shape combination design were studied by taking into consideration the plastic deformation and ductile cracking of the matrix, as well as the debonding of the matrix-particle interface. The influences of parameters on the damage mechanism of particle-reinforced metal matrix composites were also examined. The results revealed that the microstructure-based model effectively described the main material deformation and failure mechanisms. Stress concentrations mainly occurred on the aggregated particles, especially at particle sharp corners, particle-matrix interfaces, and edges along the loading direction. The stress in the matrix was much lower than that in the particles and spread at 45 degrees along the loading direction concentration. The matrix-particle debonding was insignificant, and fracture took place near the particle sharp corners. Also, the matrix failure was initiated and propagated around the particle crack tip to connect microcracks caused by particle fracture, or through high-stress/strain-concentration areas, resulting in failure of the entire workpiece. The predicted numerical data provided a better understanding of the mechanical phenomena of NbC-Fe composites at the nanoscale, which is relevant for future research on the micromechanical mechanism of NbC-Fe composites.