Lattice Softening and Phase Stability of CuZn, AgZn and AuZn β Phase Alloys

Abstract

CuZn and AuZn β phase alloys transform martensitically, but AgZn alloy does not. To clarify the origin of this difference, composition and temperature dependence of the elastic constants in CuZn, AgZn and AuZn alloys are investigated. As a result, it is found that the elastic anisotropy is large and dC'/dT is anomalously positive in all alloys, and that the alloy with the larger ordering energy has the larger lattice softening (dC'/dT). Ordering energy is suggested to play the most important role in the difference of phase diagram in these alloys.