Twin types in a room-temperature compressed magnesium alloy (Mg-3Al-1Zn) sample were identified by using electron back-scattered diffraction technique, and the results indicate that most of the twins were {10•¯2} twins and only a few of them were {10•¯1} twins. In order to study the law of atomic motion in the {10•¯1} twinning, the displacement vectors of the twinning atoms in the {10•¯1} twinning were calculated and it was found that the atomic motion could be explained using a model termed the quadrangular prism-shaped atomic group. In the latter model, there existed two types of alternately distributed quadrangular prism-shaped atomic group units in total. Though the rotational angle of the two types of quadrangular prism-shaped atomic group units in the {10•¯1} twinning was smaller than in the {10•¯2} twinning, the relative displacement magnitude in the {10•¯1} twinning was larger than in the {10•¯2} twinning due to its more complicated atomic motion, and this should be the reason that the {10•¯1} twinning was harder to occur than the {10•¯2} twinning.

Law of Atomic Motion during {10¯1¯1} Twinning in Magnesium Alloys. S.Jiang, T.Liu, C.Chen, X.Jiang: Materials Transactions, 2011, 52[8], 1585-8