碳化硼粉末放电等离子烧结电-热-力多场耦合数值模拟与实验验证

Electrical-thermal-mechanical multi-field couping numerical simulation and experimental validation of spark plasma sintering of boron carbide powder

针对碳化硼样品的放电等离子烧结,利用Drucker-Prager Cap模型描述了碳化硼粉末烧结过程中的致密化行为,从而建立了电-热-力多场耦合模型。碳化硼的热学和电学参数被定义为温度和密度的双变量函数。结果表明,模拟的电流和温度变化趋势与实验结果较吻合,最大值位于压头与模具接触位置,并且随着烧结的进行,不断向样品移动。轴向应力在样品内是主要应力,模具内周向应力为10 MPa左右,剪切应力和径向应力可以忽略不计。实验的平均相对密度为92.4%,模拟的平均相对密度为92.3%,误差为0.1%,验证了模型的准确性。

For spark plasma sintering of boron carbide sample,the Drucker-prager Cap model was used to describe the densification behavior of boron carbide powder during sintering.Then the electric-thermal-mechanical multi-field coupling model was established.The thermal and electrical parameters of boron carbide were defined as bivariate functions of temperature and density.The results show that the simulated current and temperature variation trends are in good agreement with experiment results,and the maximum value is at the contaction position of indenter and die,and moves towards the sample with the progress of sintering.Axial stress is the main stress in the sample.The circumferential stress in the die is about 10 MPa,the shear stress and the radial stress can be neglected.The average relative density of the experiment is 92.4%,the average relative density of the simulation is 92.3%,and the error is 0.1%,which verifies the accuracy of the model.