Investigation of creep deformation of particulate metal matrix composites under tri-axial loading: A micromechanics approach

In this study, we present a micromechanics model to analyze creep behavior of particle-reinforced metal matrix composites under triaxial loading. This micromechanics model enables simultaneous consideration of both matrix creep and interface diffusion creep of metal matrix composites at high temperatures. The expression of the interface diffusion creep strain rate in metal matrix composites under triaxial loading is derived, which is expressed in the tensor form and satisfies the incompressibility condition. Furthermore, the mismatch deformation between the matrix and the reinforcement phase is accounted for using Mori-Tanaka method and Eshelby’s theory, thus enabling the calculation of the stress redistribution caused by matrix creep and interface diffusion creep. A good agreement is observed between the present model and existing experimental and numerical studies. The results demonstrate that incorporating interface diffusion in the creep analysis is essential to predict creep deformation in particle-reinforced metal matrix composites. It is found that neglecting this effect may lead to a significant underestimation of creep deformation. The effects of varying stress triaxiality and volume fraction of reinforcing particles on the creep of composites are investigated utilizing an incremental creep algorithm. Specifically, the creep of composites under combined tensile-compressive loadings exhibits greater severity than under pure tensile conditions. In addition, increasing the particle volume fraction effectively reduces both the creep rate and creep deformation. This work provides a useful method for prediction of overall creep property of metal matrix composite materials under triaxial loading conditions.