热处理对挤压态7090/SiCp复合材料组织和力学性能的影响

摘要

The ultra high strength SiC particles(SiCp)reinforced Al-10％Zn-3.6％Mg-l.8％Cu-0.36％Zr-0.15％ Ni composite was prepared by spray co-deposition.Microstructures of the extruded and different heat-treated bars were analyzed by transmission electron microscopy(TEM)and energy dispersive spectrometry(EDS).Grain size of the composites prepared by two-stage solution is smaller than that by single-stage solution.After single-stage solution aging treatment,fine precipitates of both ηand AlZnMgCurich phase can be found both intragranularly and intergranularly.While after the two-stage solution,an amorphous Si-Cu-Al-O(5 nm)layer appears at the interface.The addition of Ni and Zr modified the influence of the two-stage solution and inhibited the growth of the 7090/SiCp composite grain size.Heat treatments can significantly improve the fracture toughness of the composite.The fracture toughness first decreases then increases with the elongation of the aging time.%采用喷射沉积的方法制备SiCp增强超高强Al-10％Zn-3.6％Mg-1.8％Cu-0.36％Zr-0.15％Ni复合材料.使用透射电镜(TEM)和能谱仪(EDS)对挤压并热处理过的合金棒进行微观组织取样观察.双级时效后的复合材料的晶粒比单级时效合金的晶粒更小.经单级时效处理,在晶界上和晶粒内部都可以观察到细小的η相和富AlZnMgCu相的析出颗粒.双级时效后在SiC颗粒与基体的界面上发现了一层5 nm厚的Si-Cu-Al-O非晶层.Ni、Zr的添加可以改善双级时效的效果,并且抑制7090/SiCp复合材料晶粒的生长.固溶时效处理可以显著提高复合材料的断裂韧性,而断裂韧性随着时效时间的延长而先减小后增加.