A mean-field micromechanical formulation of a nonlinear constitutive equation of a two-phase composite

In this paper, a mean-field micromechanical approach has been employed to formulate a nonlinear constitutive equation and yield conditions of a two-phase composite considering plastic and creep deformation of constituent phases. The derived constitutive equation is expressed in a piecewise linear-rate form, so it can be easily combined with common structural analyses such as a finite element analysis as well as lamination theories for typical continuous fiber-reinforced composite structures. The model has taken into account the threshold creep of constituent phases and diffusional mass transfer at the inclusion/matrix interface, which play a significant role in high-temperature deformation of short-fiber-reinforced metal matrix composites. A numerical study on anisotropy in Bauschinger effect and thermal-cycling creep of SiC whisker/Al matrix composites has been made based on the developed model.

Research highlights
► A nonlinear constitutive equation of a two phase composite is formulated.
► A mean-field micromechanical approach is employed.
► The model considers diffusional mass transfer at the inclusion/matrix interface.
► The model considers threshold creep of constituents.
► Bauschinger effect and thermal-cycling creep of short-fiber MMCs are examined.