Tensile deformation characteristics and high-plasticity mechanism of directionally solidified pure magnesium

Abstract

The pure Mg with columnar crystals was prepared by directional solidification, and the effect of process parameters on the crystal orientation and tensile properties was studied. Moreover, the microstructure evolution during tensile deformation was analyzed by electron backscatter diffraction (EBSD) technology. Furthermore, the slip within adjacent grains and grain boundary strain were discussed using the bicrystal model theory. The results show that the microstructure of the pure Mg at a pulling rate of 200 µm/s is columnar polycrystal with growth orientation concentrated in

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, and no transverse grain boundaries can be seen. In addition, the Schmid factors (SFs) of basal <a> slips in columnar crystals are higher than 0.43 under tensile stress. Moreover, the geometric compatibility factor of slip systems on both sides of grain boundaries is greater than 0.7, showing good strain coordination ability of grain boundaries. Therefore, the elongation of the directionally solidified pure Mg is as high as 53% at room temperature.

Keywords

magnesium / columnar crystal / growth orientation / geometric compatibility factor / elongation

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RIGHTS & PERMISSIONS

Central South University