Energy Dissipation and Apparent Viscosity of Semi-solid Metal during Rheological Processes PartⅡ:Apparent Viscosity  

作　　者：Wen LIU Shuming XING Peiwei BAO Milan ZHANG Liming XIAO 

机构地区：[1]Beijing Jiaotong University, Beijing 100044, China

出　　处：《Journal of Materials Science & Technology》2007年第6期801-805,共5页材料科学技术（英文版）

摘　　要：This study investigated the rheological properties of semi-solid metal. An analytical model of apparent viscosity was built up based on analysis of energy dissipation during rheological processes such as slurry preparing, delivering and model filling. The rheological properties of SSM （semi-solid metal） slurry was described by an analytical model in terms of microstructural parameters, which consist of effective solid fraction, particle size and shape, and flow parameters such as mean velocity, fluctuant velocity and relative velocity between liquid and solid phase. The model was verified in the experiment of A356 alloys with a coaxial double-bucket rheometer. And the maximum relative error between the theoretical value and measured one is less than 20%. The results of experiment and theoretical calculation also indicate that the microstructural parameters and flow parameters are two major factors that affect the apparent viscosity of semi-solid alloys, and fluctuant velocity and relative velocity between liquid and solid phase are the key factors to distinguish between steady and transient rheological properties.This study investigated the rheological properties of semi-solid metal. An analytical model of apparent viscosity was built up based on analysis of energy dissipation during rheological processes such as slurry preparing, delivering and model filling. The rheological properties of SSM （semi-solid metal） slurry was described by an analytical model in terms of microstructural parameters, which consist of effective solid fraction, particle size and shape, and flow parameters such as mean velocity, fluctuant velocity and relative velocity between liquid and solid phase. The model was verified in the experiment of A356 alloys with a coaxial double-bucket rheometer. And the maximum relative error between the theoretical value and measured one is less than 20%. The results of experiment and theoretical calculation also indicate that the microstructural parameters and flow parameters are two major factors that affect the apparent viscosity of semi-solid alloys, and fluctuant velocity and relative velocity between liquid and solid phase are the key factors to distinguish between steady and transient rheological properties.

关 键 词：Semi-solid metal Apparent viscosity Energy dissipation RHEOLOGY MODEL 

分 类 号：TG14[一般工业技术—材料科学与工程]