A Comprehensive Review on Processing and Tribological Performance of YAG Transparent Ceramics

Transparent yttrium aluminum garnet (YAG) ceramics are attracting considerable attention owing to their high optical transmittance over a broad spectral range, hardness, and fracture toughness, which make them suitable for tribological applications under extreme service conditions. This article summarizes the main processing routes for YAG transparent ceramics, including powder synthesis, calcination, the use of sintering aids, green body formation, and densification, as well as alternative approaches based on glass formation. It analyses links between processing conditions, microstructure, and mechanical and tribological behavior, with emphasis on how grain size, porosity, or dopants influence mechanical properties and tribological behavior. Available data on the mechanisms of deformation, fracture, and wear under sliding, scratching, and impact loading are reviewed, with special attention given to material removal mechanisms, including ductile‐to‐brittle transitions and crack propagation pathways, which govern tribological behavior. The review concludes with perspectives on processing optimization and dopant engineering to enhance the tribological reliability of YAG ceramics for advanced structural and defense applications.