中文摘要：

采用粉末冶金电流直加热动态热压烧结工艺，制备了混合尺寸粒子增强SiCp／Fe复合材料，研究了四种不同尺寸增强粒子的混合对铁基复合材料力学性能的影响。结果表明，合理地设计混合尺寸强化粒子利于提高铁基复合材料的力学性能，标称粒度为13ttm与23ttm的粒子组合，增强粒子体积含量10％时，小粒子与大粒子的最佳质量混合比为2：1，而含量为20％时最佳为1：1。与13um单尺寸颗粒增强SiCp／Fe复合材料相比，采用最佳比例混合尺寸粒子增强，10％SiCp／Fe复合材料的抗拉强度提高了9．79，6，而与23tLm单尺寸颗粒增强复合材料相比，其抗拉强度提高了38．39，6。混合尺寸粒子优良的增强作用是由于提高了复合材料的相对密度，减少增强粒子间的直接接触，有利于载荷从基体向强化粒子传递。

英文摘要：

Iron matrix composites reinforced with mixed size SiC particles were prepared by a powder metallurgy hot press resistance sintering technology. Investigation has been carried out on effect of mixed size reinforcing particles on the mechanical properties of the composites. It is found that the properties of the composites can be improved by rational design of size mixture of reinforcing particles. The composites reinforced with the size mixture group containing nominal sizes of 13/1m and 23um can achieve optimal mechanical properties. As the particle volume fraction in the composites is 10 %, optimal mixing ratio of 13um against 23um appears to be 2.1. However, as the particle volume fraction is increased to 20%, the optimal mixing ratio becomes 1.1. Compared to the composites reinforced with 13um or 23um single size particles respectively, the tensile strength of the 10% SiCp/Fe reinforced with optimal mixing size particles can he improved by 9.7 % or 38. 3 % respectively. The mechanisms for the better strengthening by mixed size particles are composite relative density increase, avoidance of direct contact between the reinforcing particles, and consequently more effective load transfer from the matrix to the reinforcing particles.