COMPARATIVE STUDY OF THE PHENOMENA OF PRECIPITATION IN Al–Zn–Mg ALLOY BY THE DIFFERENTIAL SCANNING CALORIMETRIC AND THE DILATOMETRY AND INTERPRETATION OF DILATOMETRIC EFFECTS

Our aim is to contribute to comprehension of the phenomena of precipitation in the Al–Zn–Mg alloys. For this, we have made a comparative study of the transformations of phases using the differential scanning calorimetric and the dilatometry. This last technique is relatively new in the case of Al–Zn–Mg alloys. It consists of two opposite effects (contraction and expansion) observed on the dilatometric curves. These effects translate two opposite metallurgical phenomena which are generally the precipitation and the dissolution.