石墨烯纳米片增强铝基复合材料的动态力学行为

Dynamic mechanical behavior of graphene nanoflakes reinforced aluminum matrix composites

采用压制-烧结-热挤压工艺制备石墨烯纳米片(GNFs)增强铝基(Al)复合材料,并对其进行压缩性能测试。结果表明:GNFs/Al复合材料是应变率敏感材料,当应变率从10^(-3)s^(-1)提高至3×10~3s^(-1)时,复合材料的强度明显提高;而当应变率继续提高至5×10~3s^(-1)时,由于材料内部发生热软化,复合材料的强度反而表现出少许下降。动态压缩后复合材料中铝基体发生动态再结晶,且应变率越高,动态再结晶越显著;增强相GNFs则发生扭曲变形后仍保持完整结构且与基体间保持原子间结合。因此,GNFs/Al复合材料具有良好的动态压缩塑性。

Graphene nanoflakes (GNFs) reinforced aluminum matrix composites were prepared by compressing-sintering-hot extrusion process, and their compressive properties were tested. The results show that GNFs/Al composites are high strain rate sensitive materials. When the strain rate increases from 10 -3 s -1 to 3×10 3s -1 , the strength of the composites increases obviously. However, when the strain rate further increases to 5×10 3s -1 , the strength of the composites declines a little due to the internal thermal softening of the material. Dynamic recrystallization occurs in the matrix of the composites after dynamic compression, and the higher the strain rate is, the more significant the dynamic recrystallization is. At the same time, the enhanced phase GNFs remain intact and bonded with matrix in atom scale while undergo a distorted deformation. Therefore, the plasticity of graphene reinforced aluminum matrix composites under dynamic compression is excellent.