Crack formation in brittle materials

摘要

Researchers use computer modeling and experimentation to study the movement of cracks at low speeds through silicon. Brittle materials such as glass and stone tend to fracture when pressure is applied. The failure mechanism for this fracture involves the initiation and propagation of a crack. The fracturing of brittle materials is an important issue that needs to be overcome in such applications as tough coatings, micromachines and armor. Dr. Noam Bernstein, research physicist with the Naval Research Laboratory in Washington, D.C., says, "Flaws or cracks are inherently present in brittle materials. The surface of a brittle material may appear to be smooth from the macroscopic standpoint, but there are microscopic cracks and little voids between grains. If enough stress is placed on a material, the longest preexisting crack can move across and produce a catastrophic failure."