The effect of sample preparation on the DSC analysis of 6061 alloy

Deformation introduced by punching had a big impact on the response of the 6061 alloy to DSC heating. Clustering at low temperatures was suppressed while the precipitation of the metastable precursors of the equilibrium β-Mg2Si phase were accelerated. The β peak in the DSC curve has transformed into a doublet when the samples were punched after the solution treatment. This change in the peak arrangement was accounted for by the operation of two distinct mechanisms for the formation of the β phase. While a fraction of the β needles has formed through evolution of the GP-1 zones, the rest had to form in the solid solution matrix. Acceleration in the kinetics of β precipitation and its transformation to β was confirmed by hardness measurements. C 2005 Springer Science + Business Media, Inc.