Origin of twin-like { 33 6 ¯ 4 } tilt boundary and associated solute segregation in a high strain rate deformed Mg-Y alloy

A high strain rate compressed Mg-Y alloy is prepared for the study of < 1 1 ¯ 00 > symmetric tilt grain boundary. A twin-like { 33 6 ¯ 4 } tilt boundary, which is formed via the evolution of { 11 2 ¯ 1 } twin boundary, is commonly found for the first time in the deformed Mg-Y alloy. Via combining high-angle annular dark-field scanning transmission electron microscopy and density functional theory calculations, the formation of { 33 6 ¯ 4 } tilt boundary and the associated segregation of Y atoms are rationalized. Such a finding provides a new vision on twinning behavior for the design of new high-performance Mg alloys.