石墨烯增强铜基复合材料的微尺度力学性能研究OA

Graphene-reinforced copper matrix composites were fabricated by spark plasma sintering(SPS).The microstructure and mechanical properties(e.g.,hardness,elastic modulus,and yield strength)of the composites were investigated by using X-ray diffraction(XRD),Raman spectroscopy,scanning electron microscopy(SEM),and instrumented micro-indentation technique.The results show that graphene retains its pristine structure and is uniformly distributed in the composites,leading to significant grain refinement.With the addition of 1.5wt.%graphene,the elastic modulus and yield strength of the composites increase by about 36%and 41%,respectively.Further analysis reveals that the grain size does not further refine with increasing graphene content,and the inter-particle spacing of graphene remains at the micron level.Therefore,grain refinement and Orowan strengthening are not significant in this study.The increased dislocation density caused by thermal mismatch residual stress due to the large difference in thermal expansion coefficients between graphene and copper may be the dominant strengthening mechanism for the copper matrix composites.