ELECTRON DIFFRACTION STUDY OF STACKING DISORDER IN PLASTICALLY DEFORMED MARTENSITE OF CU-AL ALLOY

Shifts of the electron diffraction spots of the plastically deformed β′ martensite of Cu-11.04wt.% Al alloy have been examined using the selected-area diffraction method of an electron microscope. The analysis of these shifts shows the existence of various states of stacking disorder corresponding to α=0~0.6 where α is a stacking fault parameter representing cubic type stackings. The states of staking disorder corresponding to α=0.6~1.0 are not found: instead there exist structures which are expressed as (7 1), (8 1)3, (10 1) and (11 1)3 Zhdanov notation. These structures are considered to be energetically more favorable than the f.c.c. structure for the alloy used. © 1969, THE PHYSICAL SOCIETY OF JAPAN. All rights reserved.