Metals are more ductile and ceramics are brittle?

Metals are more ductile because their atomic structure allows for the movement of dislocations, which enables them to deform plastically under stress without breaking. In contrast, ceramics have a rigid crystalline structure that makes it difficult for dislocations to move, leading to a lack of plasticity. As a result, ceramics tend to fracture under tensile stress rather than deform, making them brittle. This fundamental difference in bonding and structure accounts for the contrasting mechanical properties of these materials.