| Abstract Scope |
Advanced ceramics have excellent heat, corrosion, erosion, and wear resistance and demonstrate superior mechanical properties under demanding conditions. However, their brittle nature and low fracture toughness have posed significant barriers to structural applications. Using silicon nitride—one of the most widely used engineering ceramics—as an example, this talk provides an overview of how ceramic engineers have attempted to overcome this obstacle over the last several decades. One of the most common and effective strategies of toughening ceramics is to deliberately introduce “weak parts” into a “hard” body and induce elastic bridging and frictional pull-out of constituent substances, e.g., elongated grains, thus optimizing the body's fracture resistance. Much research effort has been devoted to adjusting the characteristics of grain boundaries to function as “weak” parts and tailoring microstructures, e.g., sizes, shapes, and orientations of grains, through innovative processing routes, leading to markedly improved fracture toughness and other properties. |