UCLA materials scientists take big step toward tougher ductile ceramics

Advance could lead to more durable, higher-performing components for spacecraft technology and tiny mechanical systems. Matthew Chin Lawrence Berkeley National Laboratory - Electron microscope image of a micrometer-scale carbide pillar carved out of a single crystal using focused ion beams. A team of materials scientists at the UCLA Henry Samueli School of Engineering and Applied Science is exploring ways to create tough ceramics, a long sought-after class of materials that would be exceptionally hard, capable of withstanding extremely high temperatures and less prone to corrosion than metals, but still have the ability to become dented or deformed without fracturing — a property called ductility. In other words, a ceramic that bends but doesn't break. The researchers focused on compounds called transition-metal carbides whose atoms are held together by three types of chemical bonds — ionic, covalent and metallic. The combination of the three bonds, researchers believe, is what makes these materials tough. To validate that hypothesis, the team performed compression tests on single crystals of two transition-metal carbides, zirconium carbide and tantalum carbide, inside a transmission electron microscope.