Toughening Ceramic Joints through Strategic Fracture Path Control

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.