超声施振深度和冷却方式对纯铝凝固组织的影响  

Effects of Depth and Method of Cooling upon Applying Ultrasonic Vibration on the Solidification Structures of Pure Aluminum

作　　者：李晓谦[1] 蒋日鹏[1] 张立华[1] 胡仕成[1] 刘荣光[1] 

机构地区：[1]中南大学机电工程学院,湖南长沙410083

出　　处：《北京理工大学学报》2008年第4期290-293,共4页Transactions of Beijing Institute of Technology

基　　金：国家“九七三”计划项目(2005CB23707)

摘　　要：在750℃对铝熔体施加功率为170 W的超声振动至其液相线温度,研究超声施振时工具杆的工作深度和熔体的不同冷却方式对铸锭凝固组织的影响,分析超声细化组织的机理.试验结果表明,经超声处理过的铝熔体凝固组织均得到不同程度的细化,超声的空化效应和声流效应对晶粒细化起主要作用.施振深度增加时,超声振动系统的机械品质因数降低,振动强度减小,输出振幅减小,超声细化效果减弱.超声细化晶粒存在一个最短必要时间,当冷却强度增大时,熔体凝固时间缩短,超声波的相对作用时间缩短,晶粒尺寸增大.Ultrasonic vibration of 170 W was imposed on an aluminum melt of 750℃ temperature. Effects of different tool rod working depths and melt cooling methods with the application of ultrasonic vibration on the solidification structure of casting ingot were studied and the mechanism of grain refinement by ultrasonic was analyzed. The results showed that solidification structures were all refined in different degrees when the aluminum melt was treated. Ultrasonic cavitation and acoustic effect played an important role in it. When depth of vibration was increased, mechanical quality factor of vibration system reduceds, vibrating intensity and amplitude output decreased, and ultrasonic refinement effect was weakened. There existed a least time of grain refinement by ultrasonic. When cooling intensity increased, melt solidifying time shortened and ultrasonic treating time shortened too, so the capacity of grain refinement was restricted and grain size grew up.

关 键 词：施振深度 冷却方式 晶粒尺寸 空化效应 声流效应 

分 类 号：TB559[理学—物理] TG249.9[理学—声学]