【摘要】 利用相场模型与溶质场进行耦合计算,模拟了二元Ni-Cu合金等温凝固的枝晶生长过程,研究了扰动对枝晶生长及溶质场和相场分布的影响。结果表明:当扰动大小取值适当时,热噪声的引入能引发侧向分枝,但不改变枝晶尖端的稳态行为;扰动可促进二次晶臂生长,加扰动后初生枝晶要长一些,即生长速度要快,枝晶形貌也更加复杂;随着扰动幅值的增大,枝晶尖端分叉程度增大;在枝晶生长过程中,枝晶尖端的浓度梯度最大,另外在被二次晶臂包围的界面区域,溶质浓度最高。更多还原

【Abstract】 The dendritic growth process of Ni-Cu alloy during isothermal solidifications was simulated with the phase-field model.Solute diffusion equation and phase-field equation were solved simultaneously.The effect of noise on the dendritic growth,solute and phase-field profile of Ni-Cu alloy were investigated.The results indicate that,when an appropriate value of disturbance is chosen,the introduction of thermal noise can induce side-branches,but it does not change the steady behavior of the dendrite tip.The noise can trigger the growth of the secondary arms,and increase the growth rate of the primary dendrite,meanwhile,the dendritic morphology become more complex.As the disturbance increasing,the bifurcated degree of dendrite tip increases;during the growth of the dendrite,the dendrite tip has the maximum concentration gradient,the addition,there is the highest concentration of the solute in the interfacial region surrounded by the secondary dendrite arm.更多还原