Abstract
Stacking fault probabilities in β' martensite of Cu-Al alloys were obtained as a function of solute content by means of X-ray diffraction. It was observed that most of diffraction lines of the powder patterns are shifted due to stacking faults, and these shifts increase with increasing aluminum content of the alloy. Fault probabilities were evaluated from the shifts of diffraction lines on the basis of Kakinoki-Komura's theory which deals with diffraction by crystals containing stacking faults. It was found that the fault probability β in the martensite increases with increasing aluminum content. This fact suggests that the β' martensite in a higher aluminum content alloy has a more tendency to approach to an h.c.p. structure.