c-axis compression twinning in an off-stoichiometric compound Ti3Al with the D019 structure

The characteristics of the c-axis compression twin in single crystals of a D019 compound Ti3Al with off-stoichiometric composition (Ti–36.5 at.%Al) have been studied by trace analysis and transmission electron microscopy. Deformation twinning is operative only at high temperatures above 1000 °C. All observed deformation twins are assigned to be of the type II and the twinning elements are determined as: K 1 : ‘ { 2 ¯   12   1 ¯ 0 ¯   3 } ’ , K 2 : { 2   0   2 ¯   1 ¯ } , η 1 : 〈 5   1 ¯   4 ¯   6 ¯ 〉 , η 2 : ‘ 〈 1 ¯   3   2 ¯   2 〉 ’ , s = 0.346.