Effects of configuration parameters on the deformation and fracture behaviors of TiB2/Cu composites with network structure: A numerical approach using an enhanced finite element model

In order to reflect the real network composites with a hard phase TiB2 surrounded by a soft phase Cu, a developed large crystal-like cell model which closer to the real cell structure is proposed in this paper. Micro-geometric features of network TiB2/Cu composites are extracted based on the actual SEM, and a stochastic synthesis algorithm is adopted to reconstruct network structure. Based on MATLAB, a 3D network model of TiB2/Cu composites is established through Voronoi algorithm. By using finite element method, the effects of configuration parameters including TiB2 particle wall thicknesses, matrix phase sizes and matrix phase morphology on the deformation and fracture behaviors in network TiB2/Cu composites are investigated, and the mechanical properties of the composites are predicted. Three failure modes including brittle fracture of particle wall, ductile damage of matrix and traction-separation law of interface are introduced in the proposed models. The experimental stress–strain curves were implemented to verify the simulation results. The results show that the trend is in good agreement and the simulation results are stable and reliable. The comprehensive mechanical properties of network composites are assessed by yield strength, elastic modulus, elongation and tensile strength. The equivalent stress and stress concentration factor of the particle wall, brittle fracture process of network, interfacial debonding, crack damage and equivalent plastic strain of matrix are quantitatively presented. It is illustrated that the bearing capacity of network TiB2/Cu composites is determined by Cu matrix, TiB2 particle wall and interface. A macro and micro structure-properties relationship of network configuration composites is established in this paper. This work provided reference and guidance for the configuration design of the network composites in the experiment.