Stresses in metal matrix composites due to machining

This paper presents a robust three-dimensional finite element model of machined particulate metal matrix composites. The model takes into consideration the thermal and mechanical interactions at the tool/chip and tool/workpiece interfaces. Temperature dependant material properties are incorporated in the model. The objective of the model is to predict the effect of the various cutting parameters on the surface integrity and subsurface damage in the produced workpiece. The model was applied to the special case of oblique turning Al/SiC particulate metal matrix composites, which are being increasingly used due to their high specific strength to weight ratio. The stress analysis revealed that high local stresses are generated in the matrix material around the particles. These stresses cause cracking in the matrix material around the reinforcing particles. The model stress results are in good agreement with the experimental SEM observations as well as micro-hardness measurements.