THE ROLE OF NICKEL CONTENT AND PORE MORPHOLOGY IN THE THERMAL AND MECHANICAL RELIABILITY OF NI-REINFORCED ALUMINA COMPOSITES

Abstract

This study presents a predictive model for the degradation of Young’s modulus in Ni/Al₂O₃ metal-ceramic composites, accounting for the coupled effects of porosity, microcrack damage, and thermal loading. The model incorporates both spherical and elongated pore geometries and evaluates the influence of nickel volume fraction on mechanical performance under high-temperature conditions. Results show that increased porosity and microcrack density, particularly due to thermal expansion mismatch and sintering stresses, significantly reduce stiffness. Elongated pores cause greater modulus degradation than spherical ones. However, higher nickel content enhances ductility and crack-bridging, mitigating damage effects and preserving structural integrity. Validation against experimental data confirms the model’s accuracy in capturing thermo-mechanical behavior. This work offers insights into optimizing Ni/Al₂O₃ composites for high-performance applications, particularly where thermal resistance and mechanical reliability are critical