The Effect of Annealing on Mechanical Properties, the Number of Fluidity, and the Size of Coherent Scattering Regions in AMg1, AMg5, and AMg6 Alloys

Abstract

The paper presents the results of research of the structural blocking influence in Al-Mg sheet aluminum alloys on the change in mechanical properties and the stamp ability after cold working and annealing. The study was provided on sheet billets of AlMg1, AlMg5 and AlMg6 alloys containing respectively 1, 5 and 6 mass.% Mg. The initial thickness of the blanks is 2.5 mm. The blanks were cold rolled with a reduction rate of 30%. To eliminate the cold working hardening alloys were subjected to annealing at temperatures of 380 and 420°C for 1 hour. The charts of tensile strength, yield stress, and elongation change are plotted, depending on the state of the samples. Stamping was evaluated by the stamping ratio σ0.2/σb. To analyze the alloys’ grain structure blocking, the change in the size of the coherent scattering areas was estimated on the basis of X-ray diffraction studies. It is established that annealing leads to a significant decrease in the tensile strength, yield stress and elongation growth of alloys AlMg1, AlMg5 and AlMg6 sheet samples in the annealing temperature interval 380...420 ̊С. Despite the high plasticity of the AlMg1 alloy, it has lower stamping characteristics than alloys with higher magnesium content (AlMg5 and AlMg6). The yield stress of alloys decreases with increasing of annealing temperature, which indicates an increase in their stamping ability after annealing. The change in the coherent scattering areas sizes in alloys depends on the magnesium content. With an increase in the magnesium content, the coherent scattering area size increase with the annealing temperature. For an AlMg1 alloy, annealing after cold rolling does not lead to a change in the coherent scattering area size.