2002 Volume 66 Issue 6 Pages 627-633
The Portevin-LeChatelier (P-L) effect in Cu-(4-10)at%Al alloys has been investigated in wide ranges of temperature and strain rate. It is shown that the occurrence of serrated flow was primarily determined by the solute concentration, that is, it did not occur in the 4.3 at%Al alloy and occurred strongly in the 10.1 at%Al alloy. It occurred weakly in the 7.4 at%Al alloy, which suggests that the Al concentration of 7 at% is the critical one for the P-L effect. It is also shown that the prediction by the Cottrell theory is inconsistent with the experimental result in the point of effects of solute concentration and strain rate on the occurrence of serrated flow. The formation of short range ordered region is proposed as a reasonable cause of the P-L effect in the alloy.
