Plastic deformation is a process by which a material undergoes permanent deformation without fracturing or breaking. This deformation occurs when a material is subjected to stress beyond its yield point, causing the material to change shape. Plastic deformation is a common phenomenon in materials science and engineering, with applications in various industries such as manufacturing, construction, and metallurgy. This process can be controlled and manipulated to achieve specific properties and characteristics in materials, making it a key area of research for scientists and engineers.