Free volume formation and the high strength of pure Mg after room temperature core-sheath ECAP passes

The present investigation is conducted to successfully deform pure Mg by equal-channel angular pressing (ECAP: channel angle 90 degrees, corner angle 20 degrees) using core-sheath configuration at room temperature. The microstructure of the sample after 4 passes of ECAP contained an average grain size of similar to 0.3 mu m and an excess free volume of similar to 0.63% due to the formation of defects and dislocations during the ECAP process. The results show that local temperature increases up to 200 degrees C during the ECAP process causes dynamic recovery and recrystallization in the microstructure during deformation. The texture analysis shows that the first pass activates the non-basal sliding systems and the 4 passes present a relatively strong (0002) fiber texture. The highest ever reported tensile toughness of SPD processed pure Mg of about 1.784 GPa% with remarkable mechanical properties were achieved after 4 passes with an ultimate tensile strength of 223 MPa, yield stress of 170 MPa, and an elongation to failure of 8%. (C) 2022 Published by Elsevier B.V.

Automated summary

This study successfully deformed pure Mg at room temperature using the core-sheath configuration and equal-channel angular pressing (ECAP) method, achieving samples with excellent mechanical properties. After 4 passes of ECAP, the microstructure of the samples changed, with an average grain size of about 0.3 μm and an excess free volume. The results also showed that the local temperature increase during the ECAP process resulted in dynamic recovery and recrystallization of the microstructure during deformation. Texture analysis revealed that the first pass activated non-basal sliding systems, while 4 passes resulted in a relatively strong (0002) fiber texture.