Preferential Orientation of α Phase With the Matrix of β′ Single Phase in Cu-41.7% Zn Alloy

The characteristic form of α phase, which always exists as a pair of plates when produced by decomposition of the matrix of β′ phase, was examined by using an embossing method and SEM observation. A prominent feature of the α phase was utilized to determine the habit plane of α phase to the matrix plane. A straight line appeared at the center of the triangular α phase as one of the feature, and this center line was almost parallel to the (002) band of SEM-ECP from the β′ matrix. At the (001) plane of β′ matrix, there are two kinds of α phase that could be divided by the inclination angle to the (Oil) band of SEM-ECP, and they were separated away by an angle of about 4° each other. At the (011) plane of β′ matrix, each plate of α phase pair was inclined about 7.3° from the (011) band of SEM-ECP from the β′ matrix. From the results mentioned above, it is concluded that the habit plane of α phase to β′ matrix exists near {5, 27, 29}_m plane of the matrix.