热处理温度对双连续β-氮化硅增强铝基复合材料性能的影响

发布时间：2018-12-09 18:29

【摘要】：通过常压烧结法制备了气孔率为53.43%的多孔氮化硅预制体,并利用挤压铸造法制备双连续β-氮化硅增强铝基复合材料,并研究了热处理温度对复合材料显微组织和力学性能的影响。利用位错增殖强化理论和界面反应理论分析复合材料的显微组织和力学性能,结果表明,随着热处理温度的升高,铝合金基体发生位错增殖,β-氮化硅增强体和铝合金基体的界面反应程度增强,复合材料的显微硬度增高,断裂韧性降低,弯曲强度先增加后降低,复合材料断裂模式从沿晶韧性断裂转变为沿晶脆性断裂。当热处理温度为850℃,复合材料的界面层厚度约为20~50 nm,其综合力学性能达到最佳。
[Abstract]:Porous silicon nitride preforms with porosity of 53.43% were prepared by atmospheric pressure sintering, and double continuous silicon nitride reinforced aluminum matrix composites were prepared by squeeze casting. The effect of heat treatment temperature on the microstructure and mechanical properties of composites was studied. The microstructure and mechanical properties of the composites were analyzed by using dislocation multiplication strengthening theory and interfacial reaction theory. The results showed that dislocation proliferation occurred in aluminum alloy matrix with the increase of heat treatment temperature. The interfacial reaction between 尾 -Si _ 3N _ 4 reinforcements and aluminum alloy matrix was enhanced, the microhardness and fracture toughness of the composites were increased, and the bending strength first increased and then decreased. The fracture mode of composites changed from intergranular ductile fracture to intergranular brittle fracture. When the heat treatment temperature is 850 鈩，

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