Effects of CNTs on dynamic recrystallization and mechanical properties of Mg-2Zn alloy sheet produced by multi-pass rolled at low temperature

A multi-pass rolling was performed to fabricate the Mg-2Zn matrix composites with different contents of carbon nanotubes (CNTs). The microstructure evolution of these composite sheets was investigated by using electron backscatter diffraction (EBSD), transmission electron microscope (TEM) and other characterization techniques. The results show that the CNTs at grain boundaries can hinder the movement of dislocations during hot rolling process. These dislocations are generally accumulated at grain boundaries, resulting in local stress concentrations which promotes the generation of the deformation twining. The dynamic recrystallization (DRX) is induced by the deformation twins, and severe DRX occurs within the twins and at the twin boundary, resulting in the weak basal textural strength of plates with high CNTs content (0.6%) in the final state. CNTs mainly affect the texture of the plate, with the increase of CNTs content, the (0001) base strength of the plate gradually decreases, and the splitting from rolling (RD) to transverse (TD) decreases the strength of the base texture. The 0.4%CNTs/ Mg-2Zn composite exhibits a weaker basal texture and the best mechanical properties. Under the strengthening of CNTs, fine grain and texture, the tensile strength, yield strength and the elongation of 0.4%CNTs/Mg-2Zn composites are 283 MPa, 260 MPa and 4%,respectively. © 2024 Central South University. All rights reserved.