Toughening Ceramic Joints through Strategic Fracture Path Control

Abstract Ceramic‐on‐ceramic joints are notorious for their inherent brittleness, posing challenges for high‐performance applications. To address this, a novel approach is proposed to enhance the involvement of filler metals during fracture. This study investigates the controlled initiation and propagation of cracks in Al₂O₃–Al₂O₃ joints through a strategic combination of laser pre‐cracking, laser patterning, and laser active brazing techniques. By introducing pre‐cracking and African daisy‐like patterning, crack propagation dynamics are altered, with cracks initially confined within pre‐crack regions before navigating through pattern intrusions. Additionally, laser active brazing effectively managed titanium diffusion, optimizing interface strength control. Evaluation via SEVNB tests demonstrated a significant enhancement in fracture toughness, achieving maximal 25.6 ± 4.6 MPa·m^0.5 compared to ≈3–5 MPa·m^0.5 for alumina ribbons. This integrated approach offers precise control over fracture paths, thereby augmenting the performance of ceramic‐on‐ceramic joints, and holds promise for advancing their applications in demanding environments.