粒度和界面原子调控对SiC/Al复合材料强度的影响

The Influence of Particle Size and Interface Atom Adjustment on the Strength of SiC/Al Composite

摘要:

SiC/Al复合材料作为一种轻质高强材料，因其优异的物理化学性能被外界广泛关注。本研究利用分子动力学方法，构建了不同SiC粒径的SiC/Al复合材料模型，根据拉伸变形模拟结果得出更小的SiC粒径有利于材料获得更高的抗拉强度。随着拉伸形变的逐渐增加，SiC颗粒在沿拉伸方向的两侧与Al基体发生分离从而产生孔隙，再从孔隙缺陷处产生位错形核并扩展至Al基体内形成塑性形变。在调节SiC/Al界面上C、Si的占位情况后，界面富Si的条件下结合更强，孔隙产生的难度增大从而对SiC/Al复合材料产生强化作用。

Abstract:

As a kind of light and high strength material, SiC/Al composite has been widely concerned because of its excellent physical and chemical properties. In this study, molecular dynamics methods were used to construct SiC/Al composite material models with different SiC particle sizes. The results of tensile deformation simulation show that smaller SiC particle size is beneficial to higher tensile strength. As the tensile deformation gradually increases, the SiC particles are separated from the Al matrix on both sides along the tensile direction to generate voids, and then dislocations are generated from the void defects to nucleate and expand into the matrix to form plastic deformation. After adjusting the occupancy of C and Si on the SiC/Al interface, it is found that the bonding is stronger when the interface is rich in Si, and the generation of voids is more difficult, which strengthens the SiC/Al composite material.