Simulated and actual micro-structure models on the indentation behaviors of particle reinforced metal matrix composites

This study investigates effects of particle volume fraction and size on the indentation behavior of Al 1080/SiC particle reinforced metal matrix composites based on both 2D simulated and actual micro-structure models using the non-linear finite element method. A simulated micro-structure model assumes randomly distributed square-shaped reinforcements through a matrix while the actual micro-structure model has a reinforcement distribution similar to an actual micro-structure taken from the section of a produced specimen. The equivalent stress and strain distributions as well as the indentation depths were compared based on both micro-structure models and experiments. Simulated and actual micro-structure models exhibited different stress and strain distributions, especially underneath the indenter. The actual micro-structure resulted in discontinuous equivalent stress and strain distributions underneath the indenter whereas the simulated micro-structure exhibited more continuous distributions. Experimental and predicted indentation depths exhibit similar trends. However, the actual micro-structure model provided an apparent improvement to predict indentation depths by decreasing differences between the experimental and predicted indentation depths as both size and especially volume fraction of the reinforced particles were increased. In general, the indentation depth was increased with decreasing volume fraction of reinforcement and increasing reinforcement particle size. The randomness of reinforcement distribution and actual micro-structure affected permanent indentation surface profiles and depths. The actual micro-structure indicated that irregular particle shape and size and randomness of particle distribution were effective parameters for predicting and understanding the indentation behavior of particle reinforced metal matrix composites.