纳米sic颗粒增强7075铝基复合材料半固态坯制备及成形分析-材料加工工程专业论文.docx

AbstractLightweight of equipment is playing an important role due to requirements for saving energy, reducing emission and improving efficiency. Lightweight of structure components provides a technical support to lightweight of equipment. It involves a replacement of steel with aluminum alloy, magnesium alloy and their composite and improvement of service level. Nano-particle reinforced aluminum matrix composite (NPAMC) has been a preferred material due to high strength and modulus and good wear resistance. However, it is relatively difficult to prepare and form nano-particle reinforced aluminum matrix composite. For example, homodisperse of nano-particle, optimization of preparing process parameters and optimal control of forming process parameters are relatively difficult. In this research, a novel method called ultrasonic-assisted semisolid stirring (UASS) is proposed firstly to solve the difficult problem of preparing NPAMC. Moreover, a typical deep cylindrical part is used as object component to investigate rheoforming of NPAMC. Effect laws of different process parameters on microstructure and mechanical properties of semisolid slurries and formed cylindrical parts are achieved on the basis of observation of microstructure and analysis of mechanical properties. It will provide a technical support for preparing and forming NPAMC.The experimental scheme was determined according to semi-solid stirring time, stirring temperature, SiCp volume fraction and time of ultrasonic vibration and applied pressure. A rheo-extrusion die was designed according to the size and shape of the cylindrical parts. Effect laws of process parameters during the UASS process on quality of semisolid billets were investigated. The results show that semi-solid stirring time, stirring temperature, SiCp volume fraction and time of ultrasonic vibration have an important influence on the preparation of semi-solid slurry, which further affects the quality of the forming cylindrical parts. The pre