电流辅助烧结过程的多物理场耦合体系模拟  

System simulation of multi-physical field coupling in electric current-assisted sintering

作　　者：谭树林 张晓敏[1] 赵志鹏 邬周志 张恒嘉 TAN Shu-lin;ZHANG Xiao-min;ZHAO Zhi-peng;WU Zhou-zhi;ZHANG Heng-jia(College of Aerospace Engineering,Chongqing University,Chongqing 400044,China)

机构地区：[1]重庆大学航空航天学院,重庆400044

出　　处：《粉末冶金技术》2020年第6期414-422,共9页Powder Metallurgy Technology

基　　金：国家自然科学基金资助项目(11872130);重庆市自然科学基金资助项目(cstc2019jcyj-msxmX0084)。

摘　　要：通过建立热–力–电–扩散强耦合结合相场模型的控制方程,对碳化硅材料的电流辅助烧结致密化机理进行了模拟研究,其中考虑了以下三个方面的影响:电流密度对烧结激活能的影响通过扩散系数引入耦合方程,在模拟中实现了活化作用实时影响扩散行为;碳化硅材料电导率与温度变化的关系;通过碳化硅烧结宏观有限元计算给出微结构演化的电流与温度边界条件。在该耦合理论体系下,对不同温升率的微结构演化全过程进行了模拟,计算所得的致密化曲线均与实验结果相符。模拟结果表明,在电流辅助烧结中,活化作用可极大促进致密化过程;提高温升率使得扩散驱动力增大,进而提高致密化速率。The densification mechanism of silicon carbide powders in electric current-assisted sintering was investigated by the phase field model based on the strongly thermo-mechano-electro-diffusional coupling theory.The influence of current density on the activation energy of sintering was introduced into the coupled equations by the diffusion coefficient,and the real-time effects of activation on the diffusion were characterized in simulation.The relationships of conductivity and temperature for the silicon carbide materials were considered.The boundary conditions of current and temperature in the morphological evolution were identified by the macroscopic finite element method during the silicon carbide sintering.The results show that,the densification curves in the microstructure evolution simulations are consistent with the experimental results under the different heating rates.The calculations indicate that,the activation can greatly promote the densification process in electric current-assisted sintering.What’s more,increasing the heating rate can also increase the diffusion driving force,thereby increasing the densification rate.

关 键 词：烧结 耦合 相场 激活能 微结构演化 

分 类 号：TF124.3[冶金工程—粉末冶金]