Experimental and finite element study of influence of heat treatment on creep behavior of short fiber reinforced metal matrix composite

Experiments and finite element analysis have been carried out to study the influence of heat treatment on the stress creep behavior of a short fiber reinforced metal matrix composite (MMC). Two heat treatments together with cast state (no heat treatment) were considered. The experimental results show that the stress creep behavior depends on the heat treatment. Under the same creep stress, the cast-state specimen has the smallest minimum creep rate and the longest creep life, while the specimens cooled in closed furnace after keeping at 550°C for 24 hours have the highest minimum creep rate and the shortest creep life. The specimen cooled in the water after keeping at 550°C for 24 hours has the middle minimum creep strain rate and middle creep life. A unit cell model was analyzed by a finite element method to reveal the stress and strain behavior in the procedures of heat treatment and stress creep experiments. The influence of heat treatments on the macro creep behavior is a combined effect relative to the residual stress and residual strain as well as their histories and can be explained by creep dissipation energy and axial stress in the fiber as well as the interfacial debonding stress. The influence of heat treatments on the macro creep behavior is a combined effect relative to the residual stress and residual stain as well as their histories, and can be explained by creep dissipation energy and axial stress in the fiber as well as the interfacial debonding stress.