固液态合金流变性能对于流动型铸造缺陷形成影响机制的分析

Analysis of Effect Mechanism for the Rheological Property of SolidLiquid State Alloy on the Defects Forming During Fluidic Casting

根据合金在固液共存状态的流变性能本构方程 ,结合凝固时补缩流动的特点 ,采用多孔介质模型 ,推导了适用于具有B K模型的固液态合金在枝晶骨架中流动的公式 ,分析了缩松的形成机理 ;运用非牛顿流体力学原理 ,推导了固液态合金中气泡、夹杂物、不同密度合金组元等在合金中作stokes流动的速度公式 ,提出了气孔夹杂。

In this paper, the equation meeting the flow in the treecrystal framework for the solidliquid BK alloy is deduced and analyses the forming mechanism of shrinkage porosity, according to the stressstain equation of rheological property for the alloy at its solidfluid state, coupling the flowing characteristic of compensating shrinkage porosity when freezing and adopting the porous medium model. Also, the velocity equation for air bubble, encrusting matter and the alloy component with different density flowing in the alloy with the stokes manner are deduced applying the nonNewton hydromechanical theory and puts forward the forming mechanism for the defects such as air bubble, encrusting matter and gravitational segregation.