Effect of the Mg contents on the annealing mechanism and shear texture of Al-Mg alloys

초록

As conventional Al-Mg alloys have a high stacking fault energy (SFE), a copper type texture evolves when it is deformed and annealed at ambient temperatures. Generally, the SFE decreases as the Mg content increases. If the SFE decreases sufficiently, the microstructure texture can change from copper to brass type. To achieve good formability with an optimal microstructure texture, severe plastic deformation (SPD) processes have been studied, and these processes mainly have shear deformation mode. As a type of SPD test, a torsion test is a method to obtain data for shear deformed materials. In this study, the effects of the Mg content on the evolution of shear and annealing textures of Al-Mg alloys were investigated using torsion tests. Al-6Mg and Al-9Mg alloys were deformed to a strain of 0.35 at a strain rate of 0.1 s(-1) at room temperature. After the materials were torsioned, an annealing process was conducted at 300 degrees C for 0-60 min for the deformed specimens. The electron backscattered diffraction technique was used to evaluate the microstructural texture of the samples after the suggested steps. As the Mg content increases under the same processing condition, a transition from copper to brass type was observed. A high Mg content resulted in an increase in stored energy. The variation in stored energy is related directly to the evolution of the annealing texture and its mechanism.

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