石墨烯/Al复合材料的显微组织和物理性能研究

Microstructure and Physical Properties of Graphene/Al Composites

铝基复合材料具有重量轻、高耐蚀性、热膨胀系数低、导电导热性能优异和加工性能优良等优点而成为当前轻金属基复合材料研究的主流,其中,石墨烯/Al复合材料是目前研究的热点方向。为了研究石墨烯含量对石墨烯/Al复合材料物理性能的影响,本文采用了冷压烧结法制备了石墨烯质量分数为0%(纯铝)、0.3%、0.6%和0.9%的石墨烯/Al复合材料,采用光学显微镜、扫描电子显微镜及其自带的能谱仪分析石墨烯/Al复合材料的微观形貌及化学成分,采用高精度固体密度仪、显微硬度计、高温DSC分析仪和激光导热系数测量仪测试分析石墨烯/Al复合材料的密度、硬度、比热容、热扩散系数和导热系数,对比分析了不同石墨烯含量对石墨烯/Al复合材料性能的影响机制。结果表明,石墨烯/Al复合材料中石墨烯均匀的分布在铝基体中,石墨烯的添加能够使基体产生明显的晶粒细化,当石墨烯含量超过0.6%时,在复合材料中出现石墨烯的团聚现象。随着石墨烯含量的增加,复合材料的密度和致密度逐渐减小,硬度值呈现先增大后减小的趋势,比热容逐渐降低,热扩散系数先增大后略微减小,导热系数缓慢上升。

Aluminum matrix composites have become mainstream in current research on light metal matrix composites because of their advantages,such as light weight,corrosion resistance,low thermal expansion coefficient,excellent electrical and thermal conductivity and excellent processing properties.Among them,graphene/Al composites are currently a hot research topic.To investigate the effect of graphene content on the physical properties of graphene/Al composites,graphene/Al composites with graphene mass fractions of 0%(pure aluminium),0.3%,0.6%and 0.9%were prepared via the cold press sintering method,and the micromorphology of the graphene/Al composites was analysed using optical microscopy,scanning electron microscopy and X-ray diffractometer.The density,hardness,specific heat capacity,thermal diffusion coefficient and thermal conductivity of the graphene/Al composites were tested and analysed using a high-precision solid densitometer,microhardness tester,high-temperature DSC analyser and laser thermal conductivity meter(LFA)to compare and analyse the mechanism of the influence of different graphene contents on the properties of the graphene/Al composites.The results show that the graphene in the graphene/Al composites is uniformly distributed in the aluminium matrix,and the addition of graphene results in obvious grain refinement in the matrix.When the graphene content is greater than 0.6 wt.%,the agglomeration of graphene is observed in the composites.With increasing graphene content,the density and densification of the graphene/Al composites gradually decrease,the hardness tends to increase and then decrease,the specific heat capacity gradually decreases,the thermal diffusion coefficient increases and then slightly decreases,and the thermal conductivity slowly increases.