Effect of solute concentration on Portevin-Le Chatelier effect in Al-Cu alloys

Abstract

The solute concentration and precipitated phase content in alloys were altered by solution treatment (ST) at different temperatures. A series of serrated load curves was obtained in tensile tests at a constant applied strain rate. The influences of solute concentration and precipitated phase content on dislocation movement were analyzed with tensile test results, and the micro-mechanism of the Portevin-Le Chatelier (PLC) effect is discussed in this paper. In the tests, when ST temperature was reduced from 500vH, the amplitude of serrated flow decreased. It reached the minimum when ST temperature was reduced to 300vH. On the other hand, the amplitude of serrated flow increased with ST temperature decreasing from 300 to 100vH. Experimental results show that when ST temperature is higher than 300vH, solute concentration is a governing factor to PLC effect; whereas when ST temperature is lower than 300vH, the precipitated phase content significantly affects the PLC effect.