Plastic deformation is a term commonly used in material science and engineering to describe the permanent deformation of a material when subjected to external forces beyond its yield strength. The word "plastic" is pronounced /ˈplæstɪk/, with the stress on the first syllable, and refers to the material's ability to change shape without breaking. "Deformation" is pronounced /dɛfɔrˈmeɪʃən/, with the stress on the second syllable, and refers to the change in shape of the material. Therefore, "plastic deformation" describes the process of a material changing shape without breaking under applied forces.
Plastic deformation is a mechanical process that occurs when a material undergoes a non-reversible change in shape due to the application of an external force. It describes the ability of a material to permanently change its shape without fracturing or breaking and is particularly relevant to ductile materials.
When subjected to stress or a force beyond its elastic limit, a material will undergo plastic deformation. This means that the material's atoms or molecules start to shift and rearrange themselves, resulting in a change in its shape. The material is able to retain its new shape even after the applied force is removed.
During plastic deformation, the material undergoes several microscopic changes, such as dislocation movements and the breaking and reforming of atomic bonds. These mechanisms allow the material to absorb energy and redistribute it throughout its structure, facilitating the permanent change in shape.
Plastic deformation is commonly observed in materials like metals, polymers, and ceramics. It is an essential property for certain applications, as it enables materials to withstand and absorb external loads and impacts without catastrophic failure. Plastic deformation is also crucial in manufacturing processes like forging, rolling, and extrusion, which shape materials into desired forms.
Understanding the behavior of plastic deformation is essential for engineers and designers, as it determines the material's strength, ductility, and resilience to applied forces.
The word "plastic" in the term "plastic deformation" comes from the Greek word "plastikos", which means "capable of being shaped or molded". In the context of materials science and engineering, plastic deformation refers to the permanent change in shape of a material under applied stress. The term "plastic" in this sense refers to the ability of certain materials to undergo such permanent deformation without fracture.