CAJ | 학술논문

在同时考虑溶质偏析的界面法向速度依赖性与局域非平衡溶质扩散的情况下，建立一个扩展的自由枝晶生长模型。与假设等溶质界面的枝晶生长模型的预测相比，从溶质枝晶到热枝晶的转变发生在更高的过冷度，即溶质控制生长发生在更宽的过冷度区域。在高过冷度区域，从热控制生长模式到纯热控制生长模式的转变没有等溶质模型所预测的急剧，而是发生在一定范围的过冷度区域。这是由于溶质偏析的界面法向速度依赖性与局域非平衡溶质扩散这两个因素共同作用的结果。模型测试表明：本模型能够对现有Ni?0.7%B(摩尔分数)合金的实验数据给出满意的描述。
재동시고필용질편석적계면법향속도의뢰성여국역비평형용질확산적정황하，건립일개확전적자유지정생장모형。여가설등용질계면적지정생장모형적예측상비，종용질지정도열지정적전변발생재경고적과랭도，즉용질공제생장발생재경관적과랭도구역。재고과랭도구역，종열공제생장모식도순열공제생장모식적전변몰유등용질모형소예측적급극，이시발생재일정범위적과랭도구역。저시유우용질편석적계면법향속도의뢰성여국역비평형용질확산저량개인소공동작용적결과。모형측시표명：본모형능구대현유Ni?0.7%B(마이분수)합금적실험수거급출만의적묘술。
Considering both the effects of the interfacial normal velocity dependence of solute segregation and the local nonequilibrium solute diffusion, an extended free dendritic growth model was analyzed. Compared with the predictions from the dendritic model with isosolutal interface assumption, the transition from solutal dendrite to thermal dendrite moves to higher undercoolings, i.e., the region of undercoolings with solute controlled growth is extended. At high undercoolings, the transition from the mainly thermal-controlled growth to the purely thermal-controlled growth is not sharp as predicted by the isosolute model, but occurs in a range of undercooling, due to both the effects of the interfacial normal velocity dependence of solute segregation and the local nonequilibrium solute diffusion. Model test indicates that the present model can give a satisfactory agreement with the available experimental data for the Ni?0.7%B (mole fraction) alloy.