中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 17 Special 1 November 2007 |
（1. Institute of Applied Physics, Jiangxi Academy of Sciences, Nanchang 330029, China;
2. State Key Laboratory of Metal Matrix Composite, Shanghai Jiao Tong University, Shanghai 200030, China;
3. Division of Materials, The University of Queensland, Brisbane, Qld, Australia 4072）
Abstract:The thermodynamic calculation of phase equilibria in the Cu-Ni-Si alloy system was carried out using the CALPHAD method. The calculations show that there are three two-phase areas and two three-phase areas in the Cu-rich parts of the isothermal section of the phase diagram at 300−600 ℃, and the three two-phase areas are FCC-A1(Cu-rich)+γ-Ni5Si2, FCC-A1(Cu-rich)+δ-Ni2Si and FCC-A1(Cu-rich)+ε-Ni3Si2, two three-phase areas are FCC-A1(Cu-rich)+γ-Ni5Si2+δ-Ni2Si and FCC-A1(Cu-rich)+δ-Ni2Si+ε-Ni3Si2. For this reason, an alloy located in the Cu-rich portion may precipitate γ-Ni5Si2, δ-Ni2Si or ε-Ni3Si2; the proportion of each phase depends on the alloy composition and aging temperature. The transmission electron microscope analysis of the Cu-3.2Ni-0.75Si alloy indicates that the precipitates are mainly δ-Ni2Si with only a few γ-Ni5Si2 phase particles, which agrees well with the thermodynamic calculations of phase equilibria.
Key words: Al-Mg-Er alloys; solidification simulation; CALPHAD
