| Englisch | Englisch The film shows the deformation of the aluminium alloys AlCuMgPb and AlCu 3 in torsion. Inhomogeneous deformation occurs on AlCuMgPb-specimens after a certain degree of deformation, i. e. the deformation concentrates on a small section of the gauge length. When this section has achieved an additional degree of deformation, the deformation zone leaps over to the adjacent region. In this way the deformation zone can move several times across the gauge length before fracture occurs. With each leap an acoustic signal is emitted. The mean propagation rate of the deformation zone decreases with decreasing strain rate and increasing degree of deformation. This so-called Portevin-Le-Chatelier-effect occurs on the AlCu 3 alloy in a modified form: several deformation fronts may be moving at the same time. The width of the deformation zone is immeasurably small and its propagation rate is very high. With the AlCu 3 alloy it was also possible to pick up sounds in the audible sound range. |
