Abstract
The crystal structure of stress-induced acicular martensite in Cu-14·2 Al-4·3 Ni (w/o) alloy was determined by the method of electron microscopy and selected-area electron diffraction. It has been shown that the stress-induced acicular martensite is different from the thermally formed martensite not only in morphology but also in crystal structure. The structure was the same as that of thermally formed β1’ martensite found in Cu–Al alloy with composition range 11 ∼ 13 (w/o) Al, and its lattice parameters were a = 4·382 Å, b = 5·356 Å and c = 38·00 Å. Thus, it is suggested that the effect of stress on martensitic transformation may be different from that of supercooling.