固相多次合成短切碳纤维增强镁合金复合材料界面结构及协同作用机制

Magnesium alloys have potential application prospects in aerospace and automotive manufacture due to their low density. However, their comprehensive applications are limited by low absolute strength and poor high-temperature performance. While the short carbon fibers can refine the grain size and improve the strength and ductility, and keep the advantage of low density, simultaneously. In this project, magnesium alloy composites with fine grains and excellent mechanical properties reinforced by short carbon fibers are prepared by solid repeated process. It is effective to solve a series of problems during melting such as oxidation and combustion of magnesium, segregation and agglomeration of carbon fibers, poor wettability and harmful interface reaction. By analyzing the effect of short carbon fibers and oxide precipitation on the microstructure (grain and substructure) and mechanical properties, the interface combined mechanism, dynamic recrystallization behavior and strengthening mechanism can be revealed, and the relation of deformation, microstructure and mechanical properties can be constructed as well. Currently, the related systematic research is rather less. This study will have important theoretical value on the control of microstructure and mechanical properties, development and application of titanium matrix composites.

基于轻质优势，镁合金在航空航天及汽车制造等领域极具发展前景，但绝对强度低、耐高温性能差等不足严重限制了其应用。短切碳纤维增强体在保证轻质优势的同时，可以细化晶粒，同时提高材料的强度和塑性。本课题提出采用固相多次合成方法制备出晶粒细小、力学性能优良的短切碳纤维增强镁合金复合材料，能有效解决熔炼过程中镁易氧化和燃烧、碳纤维易偏析和团聚、以及润湿性差和发生有害的界面反应等问题。深入分析短切碳纤维及氧化相对镁合金基体的晶粒、亚结构等微观组织和力学性能的影响规律，揭示短切碳纤维增强镁合金复合材料的界面结合机制、动态再结晶行为和强化机理，进一步构建镁合金复合材料的形变、微观特性与力学性能的相关性。目前，国内外相关研究较少，本课题研究将为镁基复合材料的组织性能调控、开发与应用提供理论支持。

基于轻质优势，镁合金在航空航天及汽车制造等领域极具发展前景，但绝对强度低、耐高温性能差等不足严重限制了其应用。固相合成技术制备短切碳纤维等碳材料增强镁基复合材料在保证轻质优势的同时，可以获得晶粒细小、力学性能优良的复合材料，而且能有效解决熔炼过程中镁易氧化和燃烧、碳纤维易偏析和团聚、以及润湿性差和发生有害的界面反应等问题，为镁基复合材料的组织性能调控、开发与应用提供理论支撑和技术支撑。. 本项目研究了挤压温度、短切碳纤维含量、固相合成次数对SCFs/AZ31复合材料微观组织和力学性能的影响，阐明了复合材料的形变、微观特性与宏观性能的相关性，揭示了其界面结合机制、动态再结晶机理和强化机制。. 采用半固态等温处理-固相合成技术制备了碳材料(短切碳纤维、石墨烯)增强AZ31复合材料，分析了基体晶粒和碳材料的微观形态及分布，阐明了复合材料微观结构和力学性能的变化规律，揭示了其界面结合机制、动态再结晶机理和强化机制。. 提出切屑水热碳化沉积法制备了Al/APC复合材料，表征了葡萄糖水热处理后形成的絮状和球状无定型碳，研究了葡萄糖浓度对Al/APC复合材料微观组织及硬度和耐磨性能的影响，揭示了耐磨机理。. 此外，固相合成了AZ91D-Nd合金、模拟了AZ91镁合金半固态组织形成过程、半固态挤压铸造成型了AZ91D镁合金发动机支架，并获得了工艺参数对微观组织和力学性能的影响规律，分析了断裂类型及断裂位置，研究界面断裂规律，讨论了界面结合机制和性能强化机制。. 发表论文10篇，其中7篇SCI收录，1篇EI收录；授权中国发明专利3项、实用新型专利2项；培养博士研究生2名，培养硕士研究生1名。