Structural changes of CuZnAl shape memory alloys during martensite aging determined by the ALCHEMI method

Abstract

The Atom Location by Channeling Enhanced Microanalysis (ALCHEMI) method has been applied to a study of the effects of aging CuZnAl shape memory alloys. In order to discover an optimum experimental condition for the ALCHEMI method, electron beam intensities in crystals of CuZnAl alloys have first been examined on the basis of the dynamical theory of electron diffraction. Under such an optimum condition, the atomic arrangement of Zn atoms in CuZnAl alloys has been investigated for both the parent and martensite phases using Cu11.4Zn18.7Al and Cu11.2Zn17.1Al(at.%) alloys, respectively. The atomic arrangement was not changed significantly by aging of the parent phase, while it was changed by that of the martensitic phase. An increase in the reverse transformation temperature was attributed to the change in atomic arrangement during martensite aging.