Vol 7, No 6 (2016) > Mechanical Engineering >

Evolution of Mechanical Behavior of Aluminum Alloy Al 7075 during Maturation Time

Ahmed Ben Mohamed, Amna Znaidi, Olfa Daghfas, Rachid Nasri

 

Abstract: The
Aluminum 7075 (Al 7075) alloy is a precipitation hardening material instead of a strain
hardening material.
These mechanical properties are of a particular
microstructure obtained by thermo-mechanical treatments. Among other things,
this is a complicated microstructure which is responsible for the mechanical
performance. The evolution of the mechanical properties of aluminum alloys is
dependent on aging time parameters
after heat treatment. In this study, the material has undergone a tempering
heat treatment followed by a series of tensile tests. The experimental data
(tensile curves in three directions during maturation time) is used to describe the
evolution of the mechanical characteristics in terms of loading directions and maturation time, denoted respectively as: Ψ and t. The tensile curves are the source of data to
begin the problem of identifying the behavior law of studied material using
Barlat’s model and Hollomon’s isotropic hardening law. Thus, from the
identified parameters (anisotropy coefficients and hardening coefficients), the
evolution of the Lankford coefficient, deformation rate and load surfaces
during the maturation time for three load directions (0°: rolling direction,
45° and 90°) are described. This study allows optimizing the response of the
aluminum alloy to plastic strains,
resulting from forming processes measured against the best time during maturation and the
best load direction.
Keywords: Aluminum 7075 alloy Al 7075; Anisotropy; Maturation time; Tensile tests; Thermo-mechanical treatments

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