放电等离子体烧结W粉数值模拟

Numerical simulation for spark plasma sintering of W powder

根据传热学以及电磁理论,在放电等离子体烧结的典型烧结条件下建立了电热耦合控制方程,利用有限元方法对W粉试样在烧结中的电热效应进行了数值模拟,得到烧结过程中电流密度、能量密度以及温度场分布。结果表明:放电等离子体烧结升温速率快,半径大小影响模具轴向温度梯度,试样径向有较高的温度梯度,影响烧结后试样的均匀性。

The control equations of electrothermal coupling were set up based on the theory of heat transfer and electromagnetics under typical spark plasma sintering（SPS） conditions.The electrothermal phenomena of tungsten powder and die and punches in sintering process were simulated using the software Comsol Multiphysics based on the finite element method.The current density,power density and temperature distribution were obtained.It＇s found that high heating rate and die radius affect temperature gradient of the graphite die in the axial direction.The axial temperature gradients of graphite die and radial temperature gradients of specimen were shown to influence the homogeneity of the product.