【摘要】 使用耦合热扰动的相场模型,对枝晶生长过程中噪声引发侧向分支的形成进行了研究。结果表明,温度场方程中加入的能量守恒噪声能够引发枝晶侧向不稳定,是侧向分支形成的主要起因;相场方程中引入的非能量守恒噪声对侧向分支的贡献不大,考虑到节省计算量,在实际计算中常将其忽略;热扰动幅值Fu对温度场的影响明显,当Fu取值适当时,热噪声可以引发侧向分支,但是不影响尖端的稳态行为。更多还原

【Abstract】 Side branching induced by fluctuations in dendritic growth is studied by using a phase-field model which incorporates thermal noise quantitatively.The calculated results indicate that conserved noise introduced in the temperature equation drives the morphological instability on the sides of dendrites and is dominant origin of side-branching,while the side branching is unaffected with inclusion of the non-conserved noise in phase-field equation,so it can be negligible from the point of view of computational saving for long simulation runs.The magnitude Fu of thermal noise influences temperature field obviously,when appropriate value is assigned to Fu,the noise can enhance the emergence of side-branching but does not influence the tip operating state.更多还原