Mechanical Stability of Bonded Dissimilar Materials When Subjected to Thermal Stresses

Author(s):

Efraín Hernández-Rivera, Matthew C. Guziewski, S. Gary Hirsch, and Brady Butler

Abstract:

The joining of dissimilar materials, such as ceramic-metal composites, for high-temperature applications is often limited by the large residual stresses induced by a mismatch in material properties during thermal processing. In this work, a closed-form thermoelastic model is extended to analyze the 2-D stress state in a bonded silicon carbide and Ti-6Al-4V bilayer system. A key aspect of the analysis is the implementation of a composite failure metric, which applies a maximum principal stress criterion for the brittle ceramic and a von Mises stress criterion for the ductile metal, providing a more realistic assessment of failure risk across the entire component. The model's predictions show qualitative agreement with a finite element simulation, confirming that maximum stresses are concentrated at the free edge and the material interface. Parametric studies demonstrate a linear dependence of maximum stress on the processing temperature change and a nonlinear relationship with the layer thickness ratio. The findings establish the closed-form model as an efficient and valuable design tool for optimizing layer geometries and thermal processing conditions to mitigate residual stresses and enhance the mechanical reliability of ceramic-metal composites in extreme environments.