PARTICULATE SIZE EFFECTS IN THE PARTICLE-REINFORCED METAL-MATRIX COMPOSITES

The influences of particle size on the mechanical properties of theparticulate metal matrix composite are obviously displayed in the experimental ob-servations. However, the phenomenon can not be predicted directly using the conven-tional elastic-plastic theory. It is because that no length scale parameters are involvedin the conventional theory. In the present research, using the strain gradient plas-ticity theory, a systematic research of the particle size effect in the particulate metalmatrix composite is carried out. The roles of many composite factors, such as: theparticle size, the Young’s modulus of the particle, the particle aspect ratio and vol-ume fraction, as well as the plastic strain hardening exponent of the matrix material,are studied in detail. In order to obtain a general understanding tor the compos-ite behavior, two kinds of particle shapes, ellipsoid and cylinder, are considered tocheck the strength dependence of the smooth or non-smooth particle surface. Finally,the prediction results will be applied to the several experiments about the ceramicparticle-reinforced metal-matrix composites. The material length scale parameter ispredicted.