CAJ | 학술논문

利用耦合溶质场与流场的相场模型,对Al-2.5Cu合金等温凝固时枝晶生长过程进行了模拟.研究了强迫对流、扰动强度及各向异性强度对枝晶生长形貌的影响.结果表明,在流场作用下,枝晶呈非对称性生长,上游的生长速度大于下游;对流影响溶质场的分布,将溶质从上游冲刷到下游,使得上游液相中的浓度低于下游;扰动强度越大,诱发的侧向分枝越多,二次枝晶越发达;各向异性强度越大,枝晶尖端的生长速度越快,曲率半径越小.
이용우합용질장여류장적상장모형,대Al-2.5Cu합금등온응고시지정생장과정진행료모의.연구료강박대류、우동강도급각향이성강도대지정생장형모적영향.결과표명,재류장작용하,지정정비대칭성생장,상유적생장속도대우하유;대류영향용질장적분포,장용질종상유충쇄도하유,사득상유액상중적농도저우하유;우동강도월대,유발적측향분지월다,이차지정월발체;각향이성강도월대,지정첨단적생장속도월쾌,곡솔반경월소.
Dendritic growth in Al-2.5Cu alloy during isothermal solidification was simulated by phase field model coupling solute field with flow field to understand effects of forced convection, noise intensity and anisotropic on dendritic morphology. The results indicate that dendrite is grown asymmetrically in condition of forced convection, where the growth velocity of upstream dendrite is faster than that of downstream dendrite. Due to the effects of convection, the solute will be washed from upstream to downstream, resulting in the upstream concentration lower than the downstream one in the liquid alloy. With increasing in noise intensity, secondary dendrite arm in upstream direction becomes more and more developed as a result of the increase of lateral branch. Meanwhile, with rising in anisotropic value, the growth velocity of dendritic tip is promoted with decreasing in curvature radius.