【摘要】 利用相场法模拟纯物质过冷熔体中的枝晶生长过程,研究各向异性强度、过冷度、扰动等对枝晶生长的影响.结果表明,扰动会促发侧向分枝的形成,但不影响枝晶尖端的稳态生长行为;随着各向异性强度的增大,枝晶尖端生长速度加快,枝晶结构特征愈加明显;过冷度的增加,枝晶尖端稳定性遭到破坏,甚至出现分叉.讨论网格步长对模拟结果的影响,指出在兼顾精度与效率的同时应优先选取粗网格.更多还原

【Abstract】 Based on a phase-field model,a series of numerical calculations of dendritic growth into undercooled melt for a pure material were performed,and the influence of some physical parameters,including anisotropy strength,undercooling and noise factor,on dendritic growth were investigated.Results showed that the noise could trigger the growth of side-branches,but this did not influence the selection of the tip operating state.The greater the anisotropy strength,the faster the tip velocity and the more obvious the characteristics of the dendritic structure.With the increase in undercooling,the stability of the tip operating state was gradually upset,and if seriously,branching-off of the dendrite tip could be seen.Finally,effect of mesh size on simulation result was discussed,and it was pointed out that the coarser mesh should be selected preferably when the resolution and time of computation is considered simultaneously.更多还原