The Study of the Hardening Precipitates and the Kinetic Precipitation. its Influence on the Mechanical Behavior of 2024 and 7075 Aluminum Alloys Used in Aeronautics

Abstract

The Research about the aluminum alloys has been in progress. Aluminum alloys, in contrast to the pure aluminum have very high mechanical characteristics of substantial resistance. These mechanical performances combined with lightness of the structure there of has a variety of uses especially in the transport sector. The aluminum alloys of the 2000 series (Cu is a main part of addition) and 7000 (Zn is the main part of addition) are essentially aeronautics alloys, hence its strong presence Air in the design of bus where Al 2024 and Al 7075 are the major part (Figure 1).

Both alloys (2024-7075) are hardening structural alloys and not by strain working. Their mechanical properties are of particular microstructure obtained from thermo-mechanical treatments. Among other things, this is a complicated microstructure which is responsible for these mechanical performances. It is interesting to examine the description of this complex phenomenon of the hardening precipitation, including areas of Guinier-Preston (GP Zone) which are very dependent on the alloy’s composition and thermo-mechanical treatments they undergo. The hardening phases (A.Deschamps2001) of 2024 and 7075 aluminum alloys are respectively (Al2Cu - Al2CuMg) and (MgZn2). These phases are obtained by precipitation of the sequence which depends on the proportions of elements alloying elements. An experimental tensile tests companion of these heat treated aluminum alloys (quenching) will allow us to understand the kinetic precipitation and its influence on the mechanical properties (Rp0.2, Rm and A%), dice quenching cool until maturation (T4).