The fabrication of large silicon nitride ceramic components is intricate and demands expertise in gas pressure liquid phase sintering (GPS-LPS). The forefront technology of finite element (FEM) thermo-mechanical modeling plays a key role in sizing aerospace components that necessitate high precision and mechanical strength. A comprehensive sintering simulation should encompass not only densification and grain growth models but also consider the heating environment, accounting for gas convection, conduction, and surface-to-surface radiation. Moreover, silicon nitride sintering simulation addresses the intricate behavior, including the swelling phenomenon during the transitions from intermediate to final stage sintering. The challenge of significant slumping in hollow parts, resulting in costly rejection, is a primary concern for industrial companies when dealing with low-viscosity liquid phase sintering. Validation of the model is achieved through the computation of simple cylindrical cases, while a meticulous comparison between simulations and sintering experiments on complex hollow bodies and deflection bars facilitates precise adjustment of the shear viscosity theoretical parameter derived from the Skorohod-Olevsky continuum theory of sintering. The findings from these simple cases guide the simulation of a complex geometry representative of typical aerospace components, determining the ideal sintering configuration to mitigate slumping issues.

中文翻译：

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Si3N4 加热和烧结的有限元模拟


大型氮化硅陶瓷部件的制造非常复杂，需要气压液相烧结 (GPS-LPS) 方面的专业知识。有限元 (FEM) 热机械建模的前沿技术在确定需要高精度和机械强度的航空航天部件尺寸方面发挥着关键作用。全面的烧结模拟不仅应包括致密化和晶粒生长模型，还应考虑加热环境，考虑气体对流、传导和表面辐射。此外，氮化硅烧结模拟解决了复杂的行为，包括从中间阶段到最终阶段烧结过渡期间的膨胀现象。空心零件的显着塌陷会导致成本高昂的报废，这是工业公司在处理低粘度液相烧结时主要担心的问题。模型的验证是通过简单圆柱形情况的计算来实现的，而复杂空心体和偏转杆的模拟和烧结实验之间的细致比较有助于精确调整源自 Skorohod-Olevsky 烧结连续体理论的剪切粘度理论参数。这些简单案例的发现可指导代表典型航空航天部件的复杂几何形状的模拟，确定理想的烧结配置以减轻塌陷问题。