Evolution of fiber lengths in a short fiber reinforced low volume fraction metal matrix composite during creep

Two steps are carried out to study the microstructure development under creep deformation in a short fiber reinforced low volume metal matrix composite (MMC) focusing on the fiber breakage and the fiber length. Firstly, the unit cell models are applied to obtain the local information on the stress states. The influence of the fiber geometric parameters and loading directions as well as the matrix/fiber interlayer on the fiber stress states has been obtained, and described quantitatively. Fiber breakage is modeled and its influence on the stress distribution has also been obtained. Secondly, based on the numerical results of the unit cell models, a statistic model has been presented for the plane randomly-distributed-fiber MMCs. The fiber breakage is taken into account. With the distribution of the geometric parameters of the fibers, the results of the statistic model agree well with published experimental results. The final fiber length is found to be little dependent on the loading conditions with applied stress states and temperature considered in this study.