Al₃Ni alloy synthesized at high pressures and its Debye temperature

The microstructures of the hypo-peritectic Al-30 wt%Ni alloy solidified at different pressures are investigated. The results show that the microstructure is composed of eutectic, Al₃Ni, and Al₃Ni₂ phases when the alloy is solidified at ambient pressure. Bulk single phase Al₃Ni alloy area (2/3) and hyper-eutectic microstructure region (1/3) co-exist after solidified at 4 GPa with a superheat degree of 800 °C. However, the eutectic and Al₃Ni phases are homogeneously distributed when the alloy is solidified at the same pressure with no superheating. It provides a new method for preparing the bulk single-phase intermetallic compound. In addition, the Debye temperatures of the single-phase Al₃Ni alloy fabricated at different pressures are explored using the low temperature heat capacity curve. The results reveal that the Debye temperatures of the single phase Al₃Ni fabricated at ambient pressure and 4 GPa are 468.95 K and 516.7 K, respectively. Finally, the lattice parameters of Al₃Ni synthesized at 4 GPa are examined using transmission electron microscopy (TEM), which shows that the lattice parameters are a = 6.6814 Å b = 7.1910 Å and c = 4.8351 Å.