Solution and precipitation effects on hot workability of 6201 alloy

Hot torsion tests were conducted in the ranges 300-500degreesC and 0.1-4 s(-1) on Al-0.8 Mg-0.7Si after either solution treatment at 500degreesC or precipitation at 300degreesC. The dependence of flow stress and ductility on temperature and strain rate were determined and the data fitted to a sinh-Arrhenius equation. Compared to material subjected to overaging precipitation, the solution treated material had a higher initial flow stress below 500degreesC and a more refined substructure, which resulted in additional shear banding. This behavior is compared to results in other Al-Mg-Si alloys in which solutioned alloys showed very high peak stresses near 300degreesC. which could be attributed to dynamic precipitation. (C) 2001 Elsevier Science B.V. All rights reserved.