（SIC_pAZ91D）镁基复合材料制备工艺的研究

【作者】 魏斌；

【导师】 颜银标；

【作者基本信息】 南京理工大学 ， 材料学， 2004， 硕士

【摘要】 本研究针对现有搅拌铸造法制备镁基复合材料的工艺局限性，通过调整SiCp加入方式、搅拌铸造法工艺参数，获得了SiCp加入新方法，制得了高收得率、颗粒分布较均匀、少气孔率的SiC_P／AZ91D复合材料坯料。同时首次应用等径角挤压工艺对搅拌铸造法制备的碳化硅颗粒增强镁基复合材料进行了变形试验，以期消除其组织固有缺陷并获得碳化硅分布均匀的组织。并用金相显微镜、扫描电镜观察和分析了等径角挤压变形前后镁基复合材料组织、断口形貌变化，结果表明：等径角挤压可以消除材料中的气孔等铸态缺陷并细化基体合金组织，改善增强颗粒均匀性；基体合金与增强颗粒的结合性能以及对SiC_P损伤的容限性得到了较大提高；铸态时SiC_P团聚为复合材料断裂的主要原因，基体合金以韧性断裂为主，伴有一定量的颗粒／基体界面脱粘，并且存在增强颗粒穿晶断裂，经ECAP后，以基体韧性撕裂为主体，SiC_P密集区域多数为颗粒／基体界面脱粘形式，存在少量增强颗粒穿晶断裂。更多还原

【Abstract】 The SiCp/AZ91D composites were fabricated with high joining ratio, uniform distribution and low pore ratio by adjusting the joining means of SiCp and the parameters of process for the localization of recent stirring-casting technologies. Meanwhile deforming tests were performed for SiCp reinforced Mg based composites prepared by stirring-casting process after equal channel angular pressing(ECAP) to eliminate the defects in the structures and obtain the uniform distribution of SiCp. The structures of Mg based composites and fracture surface were observed and analyzed by optical microscope and scanning electron microscope after ECAP. The results show that the casting defect such as pores were eliminated, the size of grains was be reduced and the uniformity of particle was improved after ECAP. The connection of matrix and particles, the harm accommodation to SiCp also were improved; SiCp masses were the main cause of fracture of the composites with tenacious fracture of the matrix alloy companied with some disconnection between particles and matrix and the cross-grain fracture exists. After ECAP, principal part was tenacious fracture of the matrix with little quantitative cross-grain fracture in the structures and disconnection between particles and matrix was the main form in the area of dense distribution of SiCp.更多还原