镍钛形状记忆合金线坯连续定向凝固温度场的数值模拟

连续定向凝固过程中结晶器的温度分布对固-液界面位置和形状具有重要影响.在建立三维物理模型以及确定材料热物性参数、边界条件与冷却水对流换热系数计算方法的基础上,采用ANSYS有限元软件对不同参数组合条件下镍钛形状记忆合金线坯连续定向凝固的稳态温度场进行了数值模拟.研究结果表明,在所给定的模型及各种参数条件下,镍钛形状记忆合金在结晶器内可以完成凝固过程,且固-液界面呈平直状,具备了进行连续定向凝固制备的基本条件.

Numerical simulation on temperature field for continuous unidirectional solidification of NiTi shape memory alloy wire billets

The temperature distribution in a crystallizer has important influence on the position and shape of solid-liquid interface during continuous unidirectional solidification. Based on the established three- dimensional physical model, simplified terms, specified material parameters in thermal and physical properties, boundary conditions, and the calculation method of heat convection of cooling water, the numerical simulation and analysis on steady-state temperature field for continuous unidirectional solidification of NiTi shape memory alloy wire billets were proceeded under the condition of different combined parameters using ANSYS finite-element software. The results indicate that the NiTi shape memory alloy completely solidifies in the crystallizer and the solid-liquid interface presents flat under the given model and various parameters, which meet the basic requirement of continuous unidirectional solidification.