Effect of particle distribution on deformation behaviour of particulate metal matrix composites

Abstract

The deformation behaviour of particle reinforced metal matrix composites was studied in the form of single and multiple particle models with experimental and numerical approaches. The responses of these models to pure applied loading and to loading incorporating thermal residual stresses were both considered. Results indicated that two particles arranged in line with the loading direction would create a stress enhancement effect, promoting localised plastic deformation. However, the four particle models showed significant suppression of the stress enhancement effect by the creation of hydrostatic stresses in the matrix region surrounding the particles. These hydrostatic stresses were generated by strong constraint from these particles of the surrounding matrix when the interparticle distance was held below a certain threshold value. In addition, if particles were spaced beyond a certain distance whereby the non-uniform stress distribution created by the individual particles could not interact, the composite mechanical behaviour would be similar to that of a single particle composite. Finally, thermal residual stresses were found to have little or no effect on the stress response of the composites at high applied loads, but could attenuate the stress state at low load levels.