(東南大學(xué) 機(jī)械系， 南京 210096)
摘 要: 研究顯微偏析數(shù)值模擬中的微觀模型和數(shù)值方法，在微觀模型中考慮了樹枝晶粗化、 固相溶質(zhì)逆擴(kuò)散、 枝晶尖端過冷、 隨溫度變化的溶質(zhì)擴(kuò)散系數(shù)等影響顯微偏析形成的動(dòng)力學(xué)因素。 數(shù)值方法中采用變網(wǎng)格技術(shù)跟蹤移動(dòng)界面，通過迭代求解溶質(zhì)擴(kuò)散方程和溶質(zhì)守恒方程計(jì)算顯微偏析參數(shù)。 并給出了微觀計(jì)算流程圖， 這種數(shù)值方法可以方便地與宏觀計(jì)算、 相圖計(jì)算相耦合。 模擬算例表明模擬結(jié)果與實(shí)驗(yàn)結(jié)果吻合較好。
關(guān)鍵字: 顯微偏析； 數(shù)值模擬； 微觀模型； 數(shù)值方法
（Department of Mechanical Engineering, Southeast University, Nanjing 210096, China）
Abstract: The numerical methods and micro models in the simulation on microsegregation were investigated. The main kinetic effects that can influence microsegregation were taken into account in the modeling such as secondary arm coarsening, solid state back diffusion, primary tip undercooling and variable diffusion coefficients according to temperature. The deforming grids technology was applied for tracking the moving interfaces, and the iterative method was applied for resolving diffusion equation and solute balance equation. The flow chart for the micro calculation which can be coupled easily with macro calculation and calculation of phase diagrams were also provided. A example calculation was carried out and the simulation results were in good agreement with experiment results.
Key words: microsegregation; simulation; micro models; numerical method
