片状粉末冶金的石墨烯/铝基复合材料制备过程控制与力学性能

石墨烯/铝复合材料具有强化效率高、强塑性协同提升、综合性能优异的特点,有望突破现有金属基复合材料强塑性匹配性差的瓶颈问题,但石墨烯的难于分散是困扰材料制备的重要问题。基于机械球磨工艺的片状粉末冶金技术可以将球状铝粉变成片状,实现石墨烯的均匀分散。本研究通过添加过程控制剂PDMS调控机械球磨过程,制备片状铝粉,结合压力浸渗技术制备0.6%(质量分数)GNPs/6061Al复合材料。结果表明:随着球磨时间延长,片状铝粉直径呈先上升后稳定的状态;随过程控制剂黏度上升,片状铝粉直径上升,铝粉片状化效果更明显,同时石墨烯缺陷含量先降低后上升。结合组织表征和力学性能测试,讨论了材料性能与组织结构间的关系。

Process control and mechanical properties of graphene/Al composites based on flaky powder metallurgy

Graphene/Al composites have the characteristics of high strengthening efficiency,synergistic improvement of strong plasticity,and excellent comprehensive performance,which is expected to break through the bottleneck problem of poor strengthplasticity matching of metal matrix composites.However,the dispersion of graphene is an important issue that plagues the preparation of materials.The flaky powder metallurgy technology based on the mechanical ball-milling process can transform the spherical aluminum powder into flakes and realize the uniform dispersion of graphene.In this study,the mechanical ball-milling process was controlled by adding a process control agent(polydimethylsiloxane,PDMS)to prepare flaky Al powder,combined with pressure infiltration technology to prepare 0.6%(mass fraction)GNPs/6061Al composites.The results show that the diameter of flaky aluminum powder increases first and then stabilizes with the prolongation of milling time.As the viscosity of process control agent increases,the diameter of flaky aluminum powder is increased,and the flaky effect of aluminum powder is more obvious.At the same time,the viscosity of graphene defect content decreases first and then increases.Moreover,it is revealed that the graphene defects show a decreasing and increasing change pattern as the viscosity increased.Combined with the structure characterization and mechanical property test,the relationship between properties and structure is discussed,which has provided a reference for the subsequent preparation of graphene/Al composites.