Morphology and preferential orientation of the rod-like α phase appearing during low temperature annealing of β' Cu-41.7% Zn alloys were investigated by SEM observation and SEM-ECP method. At the (111) plane of β' matrix, three groups of rod-like α phase intersected with each other at the angle of 60 degree between two of them. At the (001) plane of β' matrix, two groups of rod-like α phase intersected with each other at the angle of 90 degree between them. At the (011) plane of β' matrix, two groups of rod-like α phase intersected with each other at the angle of about 70 degree. In this case, another group which had shorter length than the other two groups was observed and it intersected with other groups at the angle of 55 degree.
It was estimated that the rod-like α phase might be elongated preferentially in the ‹111› direction of β' matrix. But the exact preferential direction of the rod-like α phase was not determined in this investigation because a single rod of α phase could not be selected from a bundle of rods. Thus it was not possible to establish any strict orientation relationship between the rod-like α phase and the β' matrix.
The length and radius of the lod-like α phase increased with increasing annealing time, and the activation energy for the growth of rod-like α phase was determined to be about 135-139kJ/mol.
