Microstructure and mechanical properties evaluation after annealing heat treatment of 7475-T7351 alluminum alloy

Evolução da microestrutura e propriedades mecânicas da liga de alumínio 7475-T651 após o tratamento térmico de recozimento para recristalização

Abstract

The mechanical strength of the 7XXX series aluminum alloys can be improved through cold rolling due to the hardening, however, there is a reduction on ductility, thus requiring a later stage of annealing heat treatment. The present work is aimed on the evaluation of the effects of an annealing heat treatment at 500 °C for 15 minutes, on the microstructure and mechanical properties of a cold rolled 7475-T7351 aluminum alloy with 3 mm thickness. For this purpose, it was used microstructural characterization by scanning electron microscopy / X-ray Dispersive Energy Spectrometry, and uniaxial tensile tests. It was concluded that the annealing heat treatment, promoted the matrix recrystallization, providing a decrease of the tensile strength and yield strength, and increase of the ductility. The coarse precipitates evidenced are similar and possibly Al₇Cu₂Fe and Al₂CuMg.