Size effects in the particle-reinforced metal-matrix composites

Many experimental observations have shown the influences of particle size on the mechanical properties of the particle-reinforced metal-matrix composite. However, the conventional theory cannot explain the phenomena because no length scale parameters are included in the conventional theory. In the present paper, the strain gradient theory proposed by Chen and Wang [32] is used, and a systematic research of the particle size effect in the particle-reinforced metal-matrix composite is carried out. Many composite factors, such as the particle size, the particle aspect ratio, the Young's modulus ratio of the particle to the matrix material, particle volume fraction and the strain hardening exponent of the matrix material, are investigated in detail. Two kinds of particle shapes, spheroidal particle and cylindrical particle, are considered to check the strength dependence of the particle shapes. Calculation to the special materials used by Ling [9] has been done, and the calculation results are consistent with the experimental results in Ling [9]. The material length scale parameter is predicted.