Experimental determination of solid–solid and solid–liquid interfacial energies of solid ɛ (CuZn5) in the Zn–Cu alloy

The equilibrated grain boundary groove shapes of solid ɛ (CuZn5) in equilibrium with Zn–1.75 at.% Cu peritectic liquid and solid ɛ (CuZn5) in equilibrium with solid Zn solution (Zn–2.83 at.% Cu) were observed from a quenched sample. The Gibbs–Thomson coefficient, solid–liquid interfacial energy and grain boundary energy of solid ɛ (CuZn5) in equilibrium with Zn–1.75 at.% Cu peritectic liquid have been determined to be (4.9 ± 0.3) × 10−8 K m, (76.0 ± 9.1) × 10−3 J m−2 and (150.3 ± 19.5) × 10−3 J m−2, respectively. For the first time, the equilibrated grain boundary groove shapes of solid ɛ (CuZn5) in equilibrium with solid Zn solution have been observed. The Gibbs–Thomson coefficient, solid–solid interfacial energy and grain boundary energy of solid ɛ (CuZn5) in equilibrium with solid Zn have also been determined to be (4.7 ± 0.3) × 10−8 K m, (72.9 ± 8.7) × 10−3 J m−2 and (144.1 ± 18.7) × 10−3 J m−2, respectively from the observed grain boundary groove shapes. The thermal conductivities of solid Zn solution and solid ɛ (CuZn5) phase (Zn–12 at.% Cu) have been measured with radial heat flow apparatus. The thermal conductivity ratios of the equilibrated liquid phase to solid phase for Zn–1.75 at.% Cu and Zn–12 at.% Cu alloys have also been measured with Bridgman type growth apparatus.