铝合金基体中MgAl2O4纳米晶须的原位可控生长及复合材料的增强机制

Spinel (MgAl2O4) whisker with low defect density, high temperature mechanical and chemical properties as well as high-strength and high hardness, low mismatch to aluminum lattice, has been considered as a new reinforcement of aluminum matrix composites. In this project, in situ reaction synthesis method at low temperatures will be developed to prepare nano spinel whiskers reinforced aluminum alloy matrix composites. The effects of synthesis system, sintering pressure, sintering temperature, and composition of aluminum alloy matrix on the shape, size, and amount of the spinel whisker will be investigated to optimize the parameters controlling the growth of the whiskers. Nanosize MgAl2O4 whiskers will be homogenously dispered in the matrix. The influences of whisker content, size, morphology, and distrobution of the whiskers in the matrix, as well as the aging treatment on the deformation behavior and mechanical preperites will be systematically investigated. The formation mechanism and evolution of the interface between the whisker and aluminum matrix and the interaction between the whisker-reinforced effect and age strengthening mechanism will be evaluated. The relationship among microstructure, structure and properties will be established to develop low-cost, high yield preparation techniques for aluminum matrix composites.

镁铝尖晶石（MgAl2O4）晶须具有低的晶体缺陷、稳定的高温力学性能和化学性能以及高强度和高硬度，与铝的晶格错配度低，是一种新型的铝基复合材料增强体。本项目采用在铝合金基体中原位反应合成晶须的方法制备MgAl2O4纳米晶须增强铝合金基复合材料。研究原位反应体系、烧结压力、烧结温度等成型条件以及基体铝合金成分对复合材料中原位生成晶须的形状、尺寸、含量等的影响，揭示晶须在铝合金基体内的可控生长途径，以获得在铝合金基体内均匀分布的MgAl2O4纳米晶须。研究晶须含量、尺寸、形态、分布状况以及固溶时效热处理对复合材料变形行为以及力学性能、物理性能的影响，揭示反应合成过程中晶须与铝合金基体之间的界面形成机制以及晶须强化机制和时效强化机制的交互作用机理。建立复合材料组织、结构与性能之间的关系，为原位晶须增强铝基复合材料的进一步开发和应用打下基础。