What is yield strength?

When we apply stress to a material, it deforms. Some of the deformation is plastic and the material can recover when the stress is relieved. But some deformation is permanent and the material cannot recover from it. As we apply more stress, there is more deformation. This plots on a curve in a somewhat linear, or proportional, way. But at some point, a bit more stress results in a lot more deformation, and this is the proportional limit of the material. Stress applied beyond this causes an increasing rate of deformation until the maximum or ultimate strength of the material is reached. (Beyond that it will fail completely.) Somewhere between the proportional limit and the ultimate strength of the material is the yield strength.

The yield strength of a material cannot be calculated for any material. It must be arrived at through (repeated) experiment and statistical analysis. Use the link below to the related question, and the other links to related articles that explain more about yield strength.

First answer by Quirkyquantummechanic. Last edit by Quirkyquantummechanic. Contributor trust: 2667 [recommend contributor]. Question popularity: 1 [recommend question].