放电等离子烧结粉末材料的多场耦合有限元模型及其数值模拟
Multi-field Coupled FEM Model and Simulation on Spark Plasma Sintering of Powder Material
宋 毅， 周照耀， 赖燕根， 陈志成
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作者单位：华南理工大学 机械与汽车工程学院， 广东 广州 510640
中文关键字：耦合； 有限元； 放电等离子烧结； 粉末
英文关键字：coupling; finite element method; spark plasma sintering (SPS); powder
中文摘要：提出了改进的放电等离子烧结粉末材料的有限元模型，该模型实现了温度场、电场和位移场的耦合。考虑到放电等离子烧结的一步成形工艺，将粉末材料的热电性能参数假设为温度和密度的双变量函数。结果表明，在烧结初期，接触电阻在升温过程中起到至关重要的作用；伴随着致密化进程和电流的增大，系统的最大温度区域由石墨冲头末端向粉末内部移动；引入随位移变化的接触热阻和接触电阻有助于描述接触部位的非连续温度场变化；模具热电偶位置处的实测温度和该模型的预测结果基本吻合。
英文摘要：An improved FEM model for spark plasma sintering (SPS) of powder material was proposed, which realized the couple of temperature, electrical potential and displacement. Considering the single step processing technique of SPS, the thermal-electrical properties parameters of powder material were assumed as bivariate functions of temperature and the relative density. The simulation results show that the contact electrical resistance plays a dominant role in the initial temperature field. With increasing the current and densification process, the position of the maximum temperature moves from the extremes of graphite punches into the interior of powders. The variational contact resistance with the displacement field can help describe the discontinuous temperature distributions of the contact regions better. The simulation temperature at the position of the thermo-couple is in great agreement with the experimental measurement.