Analyse thermique des alliages d'aluminium AlMgSi(Cu)

Abstract

In this work, we have undertaken the study of an Al-Mg -Si alloy of 6000 series with excess silicon of the series 6000, belongs to the category of heat treatable alloys. These alloys arouse great interest for their privilege use in the automotive and aeronautical industries. The aim of the present work is the study of the thermal expansion coefficient as a function of temperature for two categories of aluminum -based sheet in which we have introduced a wide rang e of components of transitions. From each sheet , we collected three samples following three directions: X-direction parallel to the rolling direction , Y-direction perpendicular to the rolling direction in the rolling plan and Z- direction perpendicular to the plane rolling. The dilatometric results revealed the presence of anisotropy. The thermal expansion coefficient measurements differ from one direction to another and from one alloy to another. We emphasize that the thermal expansion coefficient along Z direction of the sheet 01 contains a large landing extending over 200 C where α (T) remains substantially constant . This feature makes the material suitable in the industrial field . DSC studies enabled us to follow the transformation of the various phases of the sequence of precipitation in these alloys. The microstructure of the alloys was characterized by optical microscopy, which confirmed a significant presence of thermally stable precipitate at high temperature in the two sheets. X-ray diffraction stu dy confirms the positive role of the addition of copper , which improve s the mechanical properties of the material . Microhardness measurements show that the excess Si improves the mechanical properties of alloys Al-Mg -Si. We believe that the results obtained in this work that required the use of additional complementary techniques .