Acta metallurgica et materialia vol:41 issue:8 pages:2441-2449
Basal planes stacking sequence variation in M18R martensite of Cu-Al-Ni-Ti-Mn alloy have been studied by means of electron diffraction and lattice imaging. Samples subjected to two different homogenisation temperatures (1173 and 973K) and two different cooling rates-water quenched and air cooled were analysed. The observed changes in stacking sequence have been attributed mainly to stress accommodation around X(L) and X(S) precipitates. Very small X(SS) precipitates of the same phase have been observed and their high influence on the stacking sequence of martensite plates have been explained by means of a new ''dislocation'' mechanism related to their coherency loss into the matrix.