Ti-6Al-4V合金异形铸件离心力场下的充型与凝固

建立了离心力场下Ti-6Al-4V合金异形铸件充型及凝固过程的数学模型,通过引入附加项将离心力场模型化,采用流函数和涡函数代替描述方程中的压力项,并建立了数学模型的差分格式,总结了离心力场对Ti-6Al-4V合金异形铸件充型和凝固过程的影响规律.结果表明,在离心力场作用下,型腔内的流动由正向流动和反向流动两部分组成,初始温度分布的非对称性使凝固过程中的温度分布始终处于一种非对称状态,从而导致铸件的最后凝固区域与中心线发生偏离.

Filling and Solidification of Ti-6Al-4V Abnormity Castings in Centrifugal Field

A mathematical model for centrifugal filling and solidifying processes has been established to describe the formation of Ti-6Al-4V alloy abnormity castings.Effects of centrifugal field are simulated by two accessional terms.Stream function and eddy function are introduced to be a substitute for pressure term P to obtain the differential equation for the mathematical model.The filling and solidification in centrifugal field have been summarized based on the mathematical model established for the centrifugal cast Ti-6Al-4V abnormity castings.Calculated results showed that the flow in the cavity consists of forward flow and backward flow.The unsymmetrical initial temperature field causes continuous unsymmetrical variation in the following solidification,resulting in the final solidified region departed from the cavity axis in castings.