Abstract
The morphological change during tempering the Ni40Zn50Cu10 martensite (L10 structure) was studied by means of optical and electron microscopy. The morphology of the L10 phase changed from the martensitic structure to the massive one during tempering at 823 K. At the early stage of tempering, new interface boundaries appeared and polygonal grains were formed in a martensite plate due to the polygonization. During further tempering, many subgrains were formed. The volume fraction of the twin decreased gradually in a polygonal grain. At the late stage of tempering, large massive grains appeared and a few thin plates of (111)L10 twins existed as growth faults inside them. The surface relief of the L10 martensite disappeared gradually with the growth process of the massive grains. These phonomena were discussed briefly in relation to the recovery and the recrystallization.
