Papers by Keyword: Thermal Expansion Mismatch

Abstract: An analytical model based on multilayer structure with thermal expansion mismatch caused by temperature gradients was established to predict the residual stress in the system. The solution obtained from the model is independent of the number of layers. Three simplified models: bi-layer structure, coating system and film system with great compatibility are developed considering different engineering application. And the bilayer structure is verified by Stoney’s equation under the same conditions. Tri-layer coating system ZrO₂/ Al₂O₃/1Cr₁₈Ni₉Ti is established in order to research the effect of temperature variations on the residual stress between different layers. The results suggested the stress has obvious mutation in coating interface with different temperature variation. And the residual stress with different temperature variation in different layers is larger than that with identical temperature variation. Key words: multilayer structures; residual stress; analytical model; thermal expansion mismatch; temperature variation

Abstract: Molten Soda lime glass (SLG) was penetrated into the surface of ZTA at 1500°C for the holding time of 1 to 10 h. The depth of the glass penetration increased with increasing holding time. The thermal expansion mismatch and elastic property mismatch between the penetrated glass and ZTA produced residual compression in the surface region during cooling. This residual compression enhanced the flexural strength and fracture toughness remarkably.