Hierarchical twinning governed by defective twin boundary in metallic materials

Q Zhu and QS Huang and YZ Tian and SC Zhao and YB Chen and G Cao and KX Song and YJ Zhou and W Yang and Z Zhang and XH An and HF Zhou and JW Wang, SCIENCE ADVANCES, 8, eabn8299 (2022).

DOI: 10.1126/sciadv.abn8299

Dense networks of deformation twins endow metals and alloys with unprecedented mechanical properties. However, the formation mechanism of these hierarchical twin structures remains under debate, especially their relations with the imperfect nature of twin boundaries (TBs). Here, we investigate the intrinsic deformability of defective TBs in face-centered cubic metallic materials, where the inherent kinks on a set of primary TBs are demonstrated to facilitate the formation of secondary and hierarchical nanotwins. This defect-driven hierarchical twinning propensity is critically dependent on the kink height, which proves to be generally applicable in a variety of metals and alloys with low stacking fault energies. As a geometric extreme, a fivefold twin can be constructed via this self-activated hierarchical twinning mechanism. These findings differ from the conventional twinning mechanisms, enriching our understanding of twinning-mediated plasticity in metallic materials.

Return to Publications page