搅拌铸造法制备石墨烯增强铝基复合材料的组织和力学性能研究

石墨烯增强铝基复合材料满足轻量化用材的同时兼具良好的力学性能，是一种极具应用前景的复合材料。通过粉末混合、压坯和热还原，制备了含石墨烯的预制块，并将其作为中间体在搅拌铸造过程中加入，成功制备了石墨烯增强铝基复合材料。通过扫描电子显微镜、拉曼光谱、X射线衍射仪等表征了复合材料的微观组织结构；通过力学性能测试，研究了石墨烯含量对复合材料力学性能的影响。表征结果表明，搅拌铸造法制备的石墨烯增强铝基复合材料中石墨烯结构完整，复合材料的晶粒得到明显细化。拉伸试验表明，石墨烯质量分数为0.4%的铝基复合材料的综合力学性能最佳，抗拉强度、屈服强度和维氏硬度分别较同条件下制备的纯铝提高了55%、47%和63%。断裂机制研究结果表明，随着石墨烯含量的增加，复合材料由韧性断裂转变为脆性断裂。

Microstructure and mechanical properties of graphene reinforced Al-matrix composites prepared by stirring casting

Graphene reinforced Al-matrix composite meets the requirements of lightweight materials with high mechanical properties, and is a kind of composite with great application prospect. Graphene-contained precast blocks were prepared by powder mixing, compacting and thermal reduction. They were added as intermediates during the stir casting process, and graphene reinforced Al-matrix composites were successfully prepared. The microstructures of the composites were characterized by scanning electron microscope, Raman spectroscopy and X-ray diffractometer. The effect of graphene content on the mechanical properties of the composites was studied by mechanical properties tests. The characterization results show that the graphene structure in the graphene reinforced Al-matrix composites prepared by stir casting is complete, and the grains of the composites are obviously refined. The tensile tests results show that the Al-matrix composites with graphene mass fraction of 0.4% exhibit the best comprehensive properties, and the tensile strength, yield strength and Vickers hardness are increased by 55%, 47% and 63%, respectively, compared with the pure Al prepared under the same condition. The results of fracture mechanism research show that the composites change from ductile fracture to brittle fracture with the increase of graphene content.