The Effect of Texture on the Serrated Flow in Peak-Aged 2090 Al-Li Alloy

Abstract

Tensile specimens cut from the surface layer to the center layer of a 12.7 mm thick 2090 Al-Li alloy plate were solution treated at 550°C for 30 min and subsequently peak-aged at 190°C for 18 h. They were tensile tested along the rolling direction at 25°C at various strain rates. The solution-treated specimens gave rise to serrated flows at a strain rate of 2×10-4 s-1. On the other hand, for the peak-aged alloy, the surface-layer and subsurface-layer specimens underwent complex, serrated flows (fine and coarse types superimposed each other), whereas the center-layer and near-center-layer specimens were devoid of serrated flows. The textures of the surface-layer and subsurface-layer specimens were approximated by the {001}<110> orientation, while those of the center-layer and near-center-layer specimens were approximated by the {011}<211> orientation. The different flow behaviors were discussed based on the crystallographic textures, microstructures and the strain rates.