The f.c.c.+tetragonal two-phase region of the Cu-Ni-Zn system

The f.c.c. + tetragonal two-phase region of the Cu-Ni-Zn system has been delineated, and unit-cell parameters along the boundaries determined. Apparently anomalous parameter measurements prevented the determination of the tie lines. A pattern of diffraction broadening from the tetragonal phase common to both the two-phase and single-phase regions was related to the variation in lattice spacing of the tetragonal phase along the boundary. Reasons for this broadening are discussed.