仿生多层次构型B4C/Al复合材料压扭模块组装制备及强韧化机制研究

During service process in space environment, the spacecraft is under the complex loads. The low toughness of metal matrix composites is detrimental to their service security. In order to improve the toughness of particle reinforced aluminum matrix composites and provide the complex benefit, this project is based on nano-laminated structure of nacre. The B4C+n-Al2O3/Al building blocks will be built. The uniform distribution model for the highly ordered building block assembling strategy will also be built. Bionic compound structure will be controlled. Pressure torsion will be carried out to assemble and compact B4C+n-Al2O3/Al building blocks. The interaction among the highly ordered bionic compound structure, dispersion reinforcements and dislocations will be investigated. The relation among the ordered structure, assembling and compacting during pressure torsion process will be revealed. The strengthening and toughening mechanisms will be explored. The objective is to obtain the B4C+n-Al2O3/Al composites with the unusual combination of high strength and ductility. This project has a great significance in promoting development and application of the bionic fabrication of particle reinforced aluminum matrix composites.

航天器在空间环境服役过程中受到复杂载荷的作用，金属基复合材料的低韧性给其安全服役带来了严峻的挑战。为了提高颗粒增强铝基复合材料的韧性和充分发挥复合效益，本项目基于自然界贝壳纳米叠层复合构型，构建B4C+n-Al2O3/Al复合模块，建立模块有序组装的均匀分布模型，调控仿生复合构型，压扭组装致密B4C+n-Al2O3/Al复合模块，阐明高度有序的仿生构型、弥散增强体与位错的交互作用，揭示压扭剪切变形过程中有序构型-模块组装-致密化相互作用关系，探明仿生多层次构型的强韧化机制，实现强度和塑性匹配优良的B4C+n-Al2O3/Al复合材料压扭模块组装。项目的实施对于促进仿生制备高强韧颗粒增强铝基复合材料的发展和应用具有重要的理论意义和研究价值。

应用于空间环境铝基复合材料的低塑性，为其制备加工和安全服役带来了严峻的挑战。为了提高基体与增强体的复合效益，项目以宏微观性能-强韧化机制-构型化设计为思路，基于仿生复合构型，开展了粉体有序组装实验研究，阐明了Al粉片状化演变规律；建立了基元有序组装的均匀分布复合组元，调控基元复合构型，制备了多层次构型铝基复合材料；塑性变形调控其组织和性能，揭示变形过程中高静水压力和变形与有序叠层和弥散分布之间关系，提高了增强铝基复合材料的强度。. 完成了粉体片状球磨制备和铝基复合材料致密化等研究。结果表明：随着球磨时间不断增加，Al粉片化薄化同时会碎化。随着原始Al粉粒径增大，片状Al粉易出现焊合和团聚现象。通过球磨和热塑性变形破碎铝粉表面氧化膜，获取体积分数含量可控的Al2O3增强体。复合构型有利于提高铝基复合材料的抗拉强度。通过冷压-热处理-热塑性的致密化和有序可控复合制备，获得多层次构型铝基复合材料的抗拉强度达到188.6MPa，为高强度铝基复合材料的制备提供理论指导。