Unexpected de-twinning of strongly-textured Ti mediated by local stress

As one of the heterostructures,the layered structure has attracted extensive research interests as it could regulate the deformation mechanisms[1-3].A remarkable combination of strength and ductility has been achieved in layered metals,including CuCu[4-6],Cu-Ni[7],Cu-Al[8,9],Cu-Ti[10],Ti-Ti[11,12],and Ti-Al[13-15].During deformation,mechanical mismatch(discrepancies of yield strength,work hardening,etc.)between component layers leads to mutual constraints,which generates local stress and local strain that deviate from the applied counterparts[16-18].As a result,the activation of additional deformation mechanisms is promoted in layered metals,such as slip systems with low Schmid factor or high critical resolved shear stress[19,20].