Abstract: The microstrueture in shape memory alloy Cu—14Al—4Ni aged for two years at room temper- ature has been studied,and the substructure slow change has been observed.The domains of highly ordered phase and the transition regions appear at grain boundaries,the twin bounda- ries damage.Furthermore,the microstructure also gives the appearance and growth of antiphase domains like rectangular network.The long period antiphuse boundary structures and the antiphase domains have bee.observed first at the single diffracted vector .The con- centration gradient of solute atom Al has heen found from the matrixes to the grain bounda- ries,the matrixe is poor in Al and the grain boundaries are rich in Al.

Key words: shape memory alloy, martensite, Cu-14Al-4Ni, aging