摘要
为了研究铜元素含量变化对复合材料界面反应、微观组织结构和机械性能的影响,利用挤压铸造法制备了体积分数均为40%的Al2O3纤维增强纯铝和Al-Cu合金(1%,3%和5%)复合材料。采用X射线、TEM、SEM和拉伸实验手段,观察和测试了4种复合材料的微观组织和机械性能。结果表明,Al2O3纤维表面含有非晶SiO2成分,在高应力下易于开裂。铜元素的加入对材料的析出产生和机械性能有重要影响。铜元素引入后在复合材料中纤维表面处偏聚和富集,促进了界面θ相析出,并随基体中Cu含量提高而增加。当铜含量增加到5%后,基体内部也出现明显的析出相。拉伸实验结果表明随着Cu含量的增加复合材料的抗拉强度增高,Al2O3f/Al-Cu与Al2O3f/纯Al相比,抗拉强度分别增加了102%,146%和171%。SEM断口观察表明:基体合金的断口基本上都呈宏观脆性断口,具有低的展延性和撕裂纹理;大量的纤维从复合材料基体中拔出,一些纤维被拉断,这些特点与界面结合物和多晶的Al2O3纤维结构密切相关。
In order to study the effect of Cu content on the interfacial reaction, microstructure and mechanical properties, composite with 40% （volume fraction） reinforcement of Al2O3 fiber and matrices of pure aluminum and Al-Cu （1%, 3% and 5%） alloy was fabricated by squeeze-casting method. The microstructure and mechanical properties of the composites were observed and tested by means of XRD, TEM, SEM and tensile test. The results show that SiO2 amorphous phase exists on the surface of Al2O3 fiber and tends to rupture under high stress. The Cu element provides the most important influence on precipitation in the matrix and mechanical properties of the composites. TEM results indicate that Cu enriches at the fiber/matfix interfaces are accelerates the precipitation of θ phase. When Cu content reached 5%, θ phase precipitation could be observed in the center of the matrix. Tensile test shows that the tensile strength of the composite increases with increasing Cu content. Compared with Al2O3f/pure Al composite, the increments of the fracture strength of Al2O3f/Al-Cu composite are 102%, 146% and 171% respectively. SEM observation shows that the tensile fracture of the composite is brittle fracture. Large amount of fiber is pulled out from the matrix and some of them are ruptured. These characteristics are correlated closely with the interface combination properties and the polycrystalline structure of the Al2O3 fiber.
出处
《稀有金属》
EI
CAS
CSCD
北大核心
2005年第5期661-665,共5页
Chinese Journal of Rare Metals
基金
哈尔滨市培养学科后备带头人基金资助项目(DCQQ24405206)
