浇注温度对K4169高温合金晶粒组织影响的计算机模拟

利用Fortran语言编程,采用有限差分法分别解用热焓法处理结晶潜热的圆柱坐标系一维不稳定热传导方程,模拟了K4169高温合金圆柱锭某一横截面凝固过程中温度的变化,它正确地反映了在不同铸造工艺条件下合金铸件横截面上温度的变化规律。通过固相分数,将合金铸件凝固温度场模拟及其连续形核模型、枝晶尖端生长的动力学模型相耦合,计算了不同浇注温度下K4169高温合金圆柱锭凝固过程中晶粒组织的特征值,包括晶粒密度和平均晶粒尺寸,并参考二维CellularAutomaton方法,实现了在计算机屏幕上晶粒形成的动态显示,模拟结果和实验结果吻合较好。

Computer Simulation of Effects of Pouring Temperatures on Cast Grain Structures of Superalloy K4169

Using FDM Fortran program, the temperature evolution on a cross section of superalloy K4169 cylinder ingots was simulated through solving the heat diffusion equation with enthaply formulation. It reflected temperature evolution on the cross section of castings under various founding processes correctly. Using the fraction of solid, the simulation of temperature fields, the continuous nucleation model and growth kinetics model of the dendritic tip were coupled to calculate grain structure features of superalloy K4169 cylinder ingots during solidification at different pouring temperatures. Based on a two-dimensional Cellular Automaton technique and the grain structure features of superalloy K4169 cylinder ingots, the grains nucleation and growth of these castings were displayed on computer screen dynamically. The calculated effect of the pouring temperature on the resultant grain structure agrees well with experimental observations.