Material deformation refers to the change in shape or size of a material when subjected to external forces. This can occur in various forms, such as stretching, compressing, bending, or twisting. The extent of deformation depends on the material's properties, including its elasticity, plasticity, and tensile strength. There are two main types of deformation: elastic and plastic. Elastic deformation occurs when a material returns to its original shape after the force is removed, while plastic deformation results in a permanent change in shape. Understanding these concepts is crucial in fields like engineering and materials science, where the behavior of materials under stress is essential.