Investigation on the Curvature and Stress Distribution of Laminates Based on an Analytic Solution and FE Simulation

The potential combinations of favorable properties give metal-ceramic laminates (MCLs) a high degree of application flexibility. However, the different thermal expansion coefficients (CTEs) and shrinkage rates of the metals and ceramics during the co-sintering process often lead to large internal stresses that cause undesired deformation or even production failures. In practice, the identification of manufacturable MCLs relies on the "trial and error" principle, which usually requires a long development period. Therefore, there is a great demand for analytic and numerical methods that allow the prediction of the deformation and manufacturability of MCLs during the co-sintering process. The main objective of this study is to investigate the curvature and stress distribution in the MCLs (steel 17-4PH/ ceramic 3Y-TZP) based on the analytic solution and finite element (FE) simulation. To achieve this, the Young's moduli (E) and shear moduli (G) at high temperatures and the CTEs of both materials were measured. In addition, the curvatures and stress distributions of the two-layer and three-layer laminates were obtained based on the analytic method and FE simulation, which were in very good agreement. Furthermore, the influence of the CTE, Young's modulus, height ratio, and interface on the curvature were studied. The results showed that the CTE and height ratio have a higher influence on the curvature in comparison to the Young's modulus. The interface prevents the curvature significantly by assuming it to be a cohesive surface in the FE simulation. This provides hints to avoid delamination during the manufacturing process.