摘要
用相场法模拟了过冷纯物质二次枝晶的生长过程,并定量地研究了过冷度、各向异性、热扰动振幅等参数对二次枝晶的影响.通过加入热扰动,相场法能更真实地模拟过冷熔体中二次枝晶的生长,计算得到的二次枝晶间距和幅值与由Wentzel_Kramers_Brillouin方法得到的结果符合较好.模拟结果表明,过冷度和各向异性对二次枝晶有较大影响.当过冷度增大时,二次枝晶间距随之减小;当各向异性增大时,二次枝晶间距随之增大,但二次枝晶幅值则随之减小.热扰动振幅主要影响二次枝晶幅值,而对二次枝晶间距影响较弱.
The dendritic growth in an undercooled melt of pure substance is simulated by a phase-field model. The relationship between the dendritic growth and the parameters used in phase-field method (including undercooling, anisotropic coefficient magnitude of thermal fluctuation) has been studied quantitatively. By employing the thermal fluctuations the birth of secondary branches has been successfully simulated. The spacing and amplitude of the secondary branches are obtained, which are in reasonable agreement with those by using the Wentzel-Kramers-Brillouin approach. Simulations indicate that the undercooling and the anisotropic coefficient have remarkable influence on the growth of the secondary branches, in which secondary branch spacing decreases with the increase of undercooling, but increases with the increase of anisotropic coefficient. The amplitude of the secondary branch decreases with the increase of anisotropic coefficient. Thermal fluctuations show strong influence on the amplitude of the secondary branch, however show less influence on the secondary branch spacing.
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2005年第8期3740-3744,共5页
Acta Physica Sinica
基金
国家自然科学基金重大项目(批准号:50395101)资助的课题.~~
