Explanation

materials begins to produce the stress required for macro plastic deformation, which indicates the ability of materials to resist plastic deformation. For single crystals, when the shear stress is equal to the critical value -, the dislocation begins to multiply and move, and plastic deformation starts to occur, thus yielding. For polycrystal or engineering materials. When there is an obvious yield point, the yield strength is equal to the stress corresponding to the yield point. For the materials without obvious yield point, it is considered that the materials will yield when the plastic deformation is 0.2%. It is called conditional yielding. Then the stress corresponding to 0.2% of plastic deformation is called conditional yield strength.

Classification