Quantification of the recrystallization behaviour in Al-alloy AA1050

A new methodology for the determination of the recrystallized volume fraction from anodically etched aluminium alloys using optical microscopy is described. The method involves the creation of a composite image from multiple micrographs taken at a series of orientations. The results of quantitative analysis of images obtained by this new method are compared with those obtained using the traditional single image optical microscopy technique, orientation imaging microscopy (OIM) and microhardness indentation. The multiple orientation image method is shown to consistently yield a recrystallized volume fraction which is significantly higher than that determined from a single image while multiple orientation imaging and OIM results are found to be in good agreement. Furthermore it is shown that, after the subtraction of the effect of concurrent recovery using the rule of mixtures, microhardness indentation can also be used to determine the recrystallized volume fraction.