【摘要】 采用有限元方法模拟了DZ417G镍基高温合金定向凝固过程中的温度场、流场和界面形状的变化,考察了凝固阶段坩埚的拉速和炉子的温度梯度对流场和界面形状的影响.结果表明,随着拉速从6mm/min增加到24mm/min,凝固界面上方产生的中心向上流动的旋涡强度增加,界面的差值f从1.5mm增大到7.2mm,曲率显著增加;当拉速为6mm/min时,随着温差增加到1000℃后,凝固界面上方未产生新的旋涡,凝固界面可始终保持平界面.更多还原

【Abstract】 A finite element method was used to simulate the temperature field,flow field and interface shape in the Bridgman crystal growth of nickel based super alloy DZ417G.The effects of withdrawal rate and temperature difference in the furnace on the flow patterns and the interface between crystal and melt were analyzed.The simulation results showed that when the withdrawal rate rose from 6 to 24 mm/min,the strength of the vortices above the interface increased,so the difference of the interface increased from 1.5 to 7.2 mm.And the increase of the temperature difference was an effective way to suppress the formation of vortices above the interface.When temperature difference increased to 1000℃ and withdrawal rate was 6 mm/min,the solidification interface could be kept planar.更多还原