Abstract
When torsion is applied to an aluminum alloy bar held with chucks at a fixed distance, the material is strengthened with an appearance of spiral patterns on the surface. After that, the material is twisted in the opposite direction the same number of times. Then the shape and the surface roughness of the material are almost restored and its strength is maintained, for which this phenomenon was named ‘the Shape Restoration Phenomenon by Back-Torsion’. It is indicated that this back-torsion working makes it possible to strengthen aluminum alloy bars and aluminum alloy pipes more easily and more economically than the conventional drawing method. In this repot, deformation property of various aluminum alloy bars treated with the back-torsion working were studied.
