石墨烯纳米颗粒增强镁基复合材料界面结构和强化机理研究

Magnesium alloys are served as the lightweight structural materials, however, their application is severely restricted by the features of weak strength and low ductility. The strength and ductility of magnesium alloys can be increased simultaneously by adding minute quantity of graphene nanoparticles (GNPs). Still, it is a challenge to fabricate the GNPs/Mg composite with high volume fraction and high interfacial bonding strength. The experimental and theoretical calculation methods are adopted by the proposed research to solve this problem. This study focuses on the interfacial configuration, influences, controlled mechanism and strengthening mechanism of the power-thixoformed GNPs/AZ91 Mg-based composite. In order to get the best results of different strengthening mechanism, the corresponding mathematical model are builted to quantify them. Then the relationship among “parameters - interfacial configuration - strengthening mechanism” is explained by distinguish the strengthening mechanism contributions for the mechanical properties. Thus, the root cause of the variation for strengthening mechanism is clarified. This research took high GNPs volume magnesium based composite as an example to demonstrate the advantages the Near-Net Shaping technology of power-thixoforming in fabrication high volume fraction nanoparticle reinforced metal matrix composite. Furthermore, this study provided the theoretical basis for predicting the mechanical properties of the composite as well. The objectives of this research are to expand application fields of Mg-based composite and the semisolid forming technology.

作为轻量化结构材料，镁合金强度低、塑性差严重制约了其应用。在镁合金中加入极少量的石墨烯，可以使复合材料的强度、塑性同时增加。然而，制备高体积分数、界面强结合的石墨烯镁基复合材料仍是一项难题。为解决这一难题，拟申请项目采用实验和理论计算结合的方法，采用粉末触变成形制备石墨烯增强AZ91镁基复合材料，研究石墨烯镁基复合材料界面结构、影响因素、调控机理和强化机理，并建立强化数学模型。从而说明“工艺参数——界面结构——强化机理”关联本质，以便区分各强化机制对力学性能的贡献度，澄清强化机制改变的根本原因。该项目的研究成果，将以高体积分数石墨烯镁基复合材料为例，论证粉末触变近净成形技术制备高体积分数纳米颗粒金属基复合材料优势，为复合材料力学性能预测提供理论依据。开展这项研究将拓展镁基复合材料的应用领域，丰富半固态加工技术的研究成果。

作为轻量化结构材料，镁合金强度低、塑性差严重制约了其应用。在镁合金中加入极少量的石墨烯，可以使复合材料的强度、塑性同时增加。然而，制备高体积分数、界面强结合的石墨烯镁基复合材料仍是一项难题。针对这一难题，本项目采用实验和理论计算结合的方法，采用粉末触变成形制备石墨烯增强AZ91镁基复合材料，研究石墨烯镁基复合材料界面结构、影响因素、调控机理和强化机理，并建立强化数学模型。从而说明“工艺参数——界面结构——强化机理”关联本质，以便区分各强化机制对力学性能的贡献度，澄清强化机制改变的根本原因。结果表明，触变成形Cp/AZ91D复合材料（UTS：307MPa），相比铸态Cp/AZ91D复合材料（UTS：197MPa）抗拉强度提升了56%，相比触变成形AZ91D（UTS：253MPa）抗拉强度提升了21%。同时，触变成形复合材料的断后伸长率相比AZ91D提升了近100%。