【作者】 成守权；

【导师】 谷臣清； 赵敬忠；

【作者基本信息】 西安理工大学 ， 材料学， 2004， 硕士

【摘要】 研究了三种铝合金原位氧化生长用引发剂ZnO、MgO、SiO₂的影响作用及生长机制。在此基础上，发展了一种采用注浆成型法制备SiC／Ni预制体，通过Al-5Zn-10Si合金在高温下渗透氧化法制备Al₂O₃／SiC／Ni／Al-Si合金多相陶瓷基复合材料的新技术。采用XRD、SEM和光学显微镜以及能谱分析法，研究分析了Al₂O₃／SiC／Ni／Al-Si合金多相陶瓷基复合材料的相组成及其界面特征。 研究发现：Al-5Zn-10Si合金原位氧化生长是合金熔体通过氧化体中的微观通道传输到氧化生长体前沿继续氧化，并以胞状形式向前生长。在合金熔体表面所加的ZnO、MgO、SiO₂引发剂可缩短Al-5Zn-10Si合金氧化生长的孕育期，并有助于保持合金熔体与氧化生长体界面处微观通道的均布与畅通，从而有助于氧化生长体的均衡生长，并提高氧化生长体的致密性。 所制得的Al₂O₃／SiC／Ni／Al-Si合金多相陶瓷基复合材料的主晶相为Al₂O₃与SiC，相间存在Al（Si）复合氧化物、NiAl₂O₄及Ni与Al—Si合金相。各相界面处成分呈连续过渡变化趋势，构筑了具有模糊界面特征的多相复合体。 通过对Al₂O₃／SiC／Ni／Al-Si合金和Al₂O₃／Al两类复合材料进行热震实验，发现Al₂O₃／SiC／Ni／Al-Si合金复合材料的抗热震性能明显优于Al₂O₃／Al复合材料。表现出了西安理工大学硕士学位论文这种模糊界面对提高材料热震性的有利影响作用。更多还原

【Abstract】 The effect and growth mechanism of the dopant were contrasting investigated by ZnO, MgO and SiO2 dopants of the in-Situ Oxidation of Molten Aluminum. On the base of the study, A new preparation technique of Al2O3/SiC/Ni/Al-Si multi-phase ceramic matrix composites was developed by oxidative infiltration of Al-5Zn-10Si alloy melt into SiC/Ni performs made by slip casting at high temperature. The phase composition, microstructure and the interface characteristic were all analyzed through XRD, SEM, optical microscope, EDS, etc. The results are listed as follows:The growth mechanism of Al-5Zn-10Si alloy is that molten aluminum keep a continuous oxidation and growth in the way of cell-shape through the micro-channels which transfer the molten aluminum to the reaction front. The dopants of ZnO,MgO,SiO2 coated on the surface of Al-5Zn-10Si alloy can shorten the incubation period of Al-5Zn-10Si alloy directed oxidation process markedly, and keep the micro-channels homogeneous and unblocked, thereby redound to uniformly growing of the A12O3/ Al composite, and increase the its relative density.The main phase of the Al2O3/SiC/Ni/AI-Si multi-phase ceramic matrix composites include A12O3 and SiC,Al (Si) compound oxide, NiAl2O4 , Ni and Al-Si alloy phase exist in the interface of A12O3 phases or SiC phases. The composition in different phase interface is continuous variety, consequently formation the multi-phase composites with vague interfacewas formed.The thermal shock resistance experiments of the Al2O3/SiC/Ni/Al-Si composites and the A12O3/A1 composites were comparatively studied. The results show that the thermal shock resistance of the Al2O3/SiC/Ni/Al-Si composites are preferable to that of the A12O3/A1 composites obviously. It indicated that the vague interface was favorable to improve the thermal shock resistance of materials.更多还原