Interface Strength, Damage and Fracture between Ceramic Films and Metallic Substrates

Ceramic films on metallic substrates are widely used in engineering applications, but their performance depends heavily on interface properties. Prior research has shown that factors like film thickness, grain size, and residual stress influence interface strength and fracture behavior. However, the exact mechanisms of how these factors interact remain unclear. This uncertainty drives the need for detailed simulation studies. Existing models often lack the resolution to capture nanoscale effects. Residual stress effects are also not fully understood. Previous experimental findings suggest grain size affects interface strength. Yet, the speed of damage propagation and its relation to film thickness is not well established. This gap motivated the development of a three-dimensional finite element model. The goal is to better understand how interface properties evolve under tensile loading.

This study aimed to investigate the interface damage and fracture behavior between ceramic films and metallic substrates. The focus was on how film thickness, grain size, and residual stress influence interface strength. The researchers used a three-dimensional finite element model to simulate these effects. The model incorporated cohesive elements at the interface to capture damage evolution. The study also sought to determine how residual stress affects interface properties. The simulations were based on thermodynamic definitions of fracture energy. The goal was to provide insights into how to design more reliable ceramic-metal composite structures. By understanding these factors, engineers can improve the durability of related parts.

The researchers developed a three-dimensional finite element model of alumina films on Ni substrates. Cohesive elements were used to simulate the interface between the film and substrate. The model allowed for the simulation of interface damage and fracture behavior under tensile loading. Interface fracture energy was calculated using its thermodynamic definition. The simulation captured Mises stress distribution and damage evolution in the film-substrate system. The effects of grain size, film thickness, and residual stress were systematically analyzed. The model was validated against previous experimental results on nanoscale grain effects. The simulations provided a detailed view of how interface properties change under different conditions.

The simulations showed that nanoscale grain size significantly increases interface strength. This finding aligns with prior experimental observations. Interface strength decreases with increasing radial residual force. Axial residual pressure, however, increases interface strength. As film thickness increases, interface strength remains constant. However, the speed of interface damage increases with thickness. Thicker films exhibit more rapid fracture propagation. The underlying mechanism of damage speed was analyzed in detail. These results provide a clearer understanding of how interface properties evolve under tensile loading.

The study found that grain size and residual stress strongly influence interface strength and fracture behavior. Nanoscale grain size increases interface strength, while radial residual force decreases it. Axial residual pressure enhances interface strength. Film thickness does not change interface strength but accelerates damage propagation. These findings help explain how interface properties evolve under tensile loading. The results suggest that controlling grain size and residual stress can improve the reliability of ceramic-metal interfaces. The study provides a framework for designing ceramic-metal composite structures with better performance. These insights may guide future design and manufacturing processes.