【作者】 刘海；

【导师】 刘昌明；

【作者基本信息】 重庆大学 ， 材料加工工程， 2007， 硕士

【摘要】 本论文重点研究了机械搅拌法制备SiC颗粒增强ZL104合金复合材料的制备工艺,同时对制备的复合材料浆料进行了离心铸造成形工艺的研究。研究表明自行设计的制备装置合理可行,研究工艺清晰,制备出了分布均匀、结合良好的颗粒增强铝基复合材料,离心铸造成形零件完整光洁、组织致密,性能优良。根据机械搅拌法制备颗粒增强铝基复合材料的工艺原理,自行设计了一套集熔炼、搅拌、气体保护为一体的整套装置,布局合理,操作方便。搅拌复合之前,对SiC颗粒进行了600℃的高温焙烧预处理;在熔炼制备过程中,选择合适的熔体温度加入经200℃预热的SiC颗粒,使搅拌器在高速旋转下产生漩涡把颗粒卷入到熔体中,然后根据熔体液面情况进行及时的调整,使搅拌器保持合理的位置和搅拌速度,保证搅拌引起的旋涡不要过大,以减少气体的卷入和基体金属的氧化。研究中采用了每分钟825转的转速进行了100分钟的稳定搅拌分散工艺过程。将制备的复合材料浆料重力浇注成棒料试样,观测其微观组织,结果表明:在通过机械搅拌法一次性制备近30Kg的小直径(15μm)SiC颗粒增强铝基复合材料中,颗粒分布均匀,界面结合良好。把搅拌制备好的复合材料浆料离心铸造成形圆盘状零件,复合材料在高速旋转的金属型模具中凝固成形。实验表明:复合材料流动性能好,充型能力强,成形零件外形完整,表面光滑整洁。对成形零件进行微观组织观察和孔隙率测试,结果表明:复合材料离心铸造成形零件组织致密、结合良好、孔隙率下降至3%以内,相对于重力浇注棒料有了明显的改善。选取工艺相同的三个复合材料离心铸造成形零件,把其中两个零件分别进行T5和T6热处理,进行拉伸性能测试,结果表明固溶时效热处理工艺强化了颗粒增强铝基复合材料的力学性能,T5热处理后抗拉强度达到182 MPa,相对于未经热处理零件抗拉强度137 MPa有了较大的提升,T6热处理后零件的抗拉强度不及T5热处理;零件的硬度值也有同样的变化趋势。研究表明:机械搅拌法制备颗粒增强铝基复合材料和离心铸造成形复合材料零件是研究和推广金属基复合材料应用的有效方法;热处理强化颗粒增强铝基复合材料方法可行。更多还原

【Abstract】 The main task of this paper is to research the manufacturing process of ZL104 alloy composites reinforced by SiC particles and the centrifugal casting process of composites has been studied too. The result indicates that the equipment and process are feasible. The particle is dispersive and well combined with the matrix alloy. The part formed by centrifugal casting has integrated figuration, dense microstructure and fine properties.According to the principle of manufacturing composite by mechanical stirring, a set of equipment for melting、stirring and gas protection has been designed, which is reasonable and convenient to handle. SiC particles are pretreated at 600℃before stirring. During the fusing, when fusion is at appropriate temperature, put the particle, which is preheated to 200℃, into it and immix the fusion and particle by the whirlpool made by the running stirrer. Adjust the position and stirring speed of the stirrer according to the fusion surface situation to assure the whirlpool is not too great, in order to reduce air immixture with the fusion and the oxidation of the matrix alloy. The rotate speed adopted in this research is 825r/min and stirring for 100 minutes stably. The composite is gravity-assist pouring into billets. The microstructure of the sample has been studied and analyzed. The result indicates that the aluminum matrix composite, with the weight of nearly 30kg, reinforced with small dimension (15μm) of SiC particles was manufactured, and the particles dispersed in the matrix uniformly and interface combined great.The disc-like part is formed in the metallic mould, which revolves at a high speed by centrifugal casting, with the prepared composites. The experiment shows that the fluidity of the composite is good, the formation ability is great too and the figuration of the part with slippery surface is integrated.The microstructure and air hole ratio of the parts have been analyzed. The result shows that the combination of the part formed by centrifugal casting is nice, structure is dense and the air hole ratio is reduced to 3% improved obviously comparing to the part formed by gravity-assist pouring. Choose three parts formed by centrifugal casting in same technology and two parts of them are heat treated by T5 and T6, separately. And then test their mechanical properties. The results show that solid solution and aging heat treatment improve the mechanical properties of the Aluminum matrix composite reinforced by particle. Tensile strength reaches to 182MPa after T5 heat treatment, which is higher than the part heat treated by T6, and improves greatly compared to non-heat treatment, which is 137MPa. Hardness of the parts changes in the same trend.The research shows that preparing the aluminum matrix composites by mechanical stirring and forming parts by centrifugal casting are available methods to research and extend the application of metal matrix composites. It is feasible to reinforce the aluminum matrix composites through heat treatment.更多还原