Yield stress after double strain-path change

Two different types of complex loading paths, with three strain paths (roll ing-rolling-tension), were carried on a polycrystalline copper sheet. The f irst and second paths in rolling were performed perpendicular to each other . Depending on the case, the last strain path in tension was considered to be parallel to the first or second rolling path. The effect of double strai n path change on the subsequent reloading yield stress is studied in this w ork. The results show that the behavior after prestraining depends mainly o n the orientation relationship between the previous (rolling-rolling) and t he subsequent (tension) paths and less on the order in which they have been performed. The mechanical behavior in reloading is discussed on the basis of a statistical study of the slip systems that remain active after path ch ange. (C) 2000 Elsevier Science S.A. All rights reserved.