Evolution of deformation mechanisms and their orientation dependence in fine-grained Mg-3Gd during tension

Magnesium alloys usually exhibit poor ductility attributed to their intrinsic hexagonal close-packed (hcp) structure, which fails to provide sufficient independent slip systems for homogeneous deformation. Here we demonstrate that multiple deformation mechanisms can be activated with increasing tensile strain in a fine-grained Mg-3Gd with a weak basal texture. ( c + a ) slip, tension twinning and compression/double twinning exhibit a high orientation dependence at an early stage of deformation, whereas the orientation dependence becomes less obvious with further increasing strain. The high work hardening rate at the strain of 2%-5% is accompanied by the significant increase of ( c + a ) slip and tension twinning activities. The fine microstructure strongly restricts the activation and growth of twinning, resulting in a slow exhaust of tension twinning and thin compression twins. The restriction of twinning and the activation of profuse ( c + a ) slip near grain/twin boundaries, relaxing the stress concentration, sustain the homogeneous deformation to a high strain. (c) 2024 Chongqing University. Publishing services provided by Elsevier B.V. on behalf of KeAi Communications Co. Ltd. This is an open access article under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ ) Peer review under responsibility of Chongqing University