Stacking Disorder in Martensite of Cu-Zn Alloy

The faulting in stacking sequence of close-packed layers of the martensite in Cu–38.6 at. %Zn alloy has been studied by electron diffraction, utilizing the selected area diffraction technique of electron microscopy. Observed diffraction spots were shifted and diffused owing to the stacking faults. The shifts of sports were analyzed by the Kakinoki-Komura theory with Reichweite s =3, and the stacking fault probabilities α were found to be between 0.13 and 0.43, α being a fault parameter representing the cubic type stacking faults. The result is compared with the case of the Cu-Al martensite: the predominant type of stacking faults is cubic type for the Cu-Zn martensite while hexagonal type for the Cu-Al martensite. This difference is explained by the phenomenological theory of martensitic transformation.