Numerical Study on Mechanical Properties of Discontinuously Reinforced Titanium Matrix Composite with Network Reinforcement Architecture

A two-step finite element modeling method is adopted to predict the elastic properties and reveal the strengthening mechanisms of discontinuously reinforced titanium matrix composites (DRTMCs) with network reinforcement architecture. The microstructure of the composite consists of reinforcement-rich phase (Phase I) and reinforcement-lean phase (Phase II). In the first step, the mechanical properties of Phase I with varying whisker reinforcement content are calculated. In the second step, the calculated mechanical properties are used as input parameters for the homogenized Phase I in the representative volume elements (RVEs) of the composites. In addition, a direct procedure is adopted to generate the exact RVE to validate the two-step method. The predicted elastic moduli obtained by the two-step procedure agree well with those from experiments. Following the same procedure, the strength increase of the composites contributed by the two mechanisms, i.e., load-transfer by the reinforcement and matrix strengthening caused by grain refinement, solution strengthening, etc., can be determined from the simulations separately, which shows that the strength enhancement of the DRTMCs with the addition of TiB whiskers by in situ reaction is primarily due to the matrix strengthening rather than the load-transfer mechanism.