Stretching (material technology)

When stretching is called the defined deformation of materials to achieve anisotropic mechanical properties. If, for example, plastics are subjected to tensile stress during deformation, the disordered polymers and the partially crystalline areas align roughly parallel to the direction of tension. As a result of this measure, the contact surfaces between the macromolecules become larger and the distance smaller. As a result, the secondary bonds become stronger. The stretched plastic has significantly increased its mechanical strength in the stretching direction. In addition to the secondary bonds, the fixed primary bonds also act here, while only secondary bonds are effective across them.

Similar effects can also be found in metals , for example described by the Bauschinger effect .