“…In the present study, these eleven types of η precipitates are proposed to be classified into four groups according to their habit planes, as illustrated in Table 2. Based on the nomenclature used by Degischer et al [9], the (0001) basal planes of η 1 , η 4 , η 9 , and η 11 (designated as Group 1) and those of η 2 , η 3 , and η 10 (designated as Group 2) are parallel to the (110) Al and (11 ത 1 ത ) Al habit planes, respectively. The η 5 , η 6 , and η 7 (designated as Group 3) and the η 8 (designated as Group 4) grow on the (1 ത 21 ത 0) planes parallel to the (11 ത 1 ത ) Al and (11 ത 2) Al habit planes, respectively.…”