Cu-Ni-Sn三元系相平衡的热力学计算

基于Cu-Ni-Sn三元系的相平衡和热力学的实验信息,采用亚正规溶体模型描述液相和fcc相的Gibbs自由能,为了预测该体系中bcc相的A2-B2有序-无序转变,bcc相的Gibbs自由能采用双亚点阵模型进行描述.利用CALPHAD(相图计算)方法评估了Cu-Ni-Sn三元系各相的热力学参数,计算的富Cu侧相图和热力学性质与实验数据比较一致.并对该三元系中bcc相的A2-B2有序-无序转变及fcc相的溶解度间隙进行了计算.这些计算结果对利用析出强化以及Spinodal分解开发高强度和高导电性的新型Cu基合金的组织设计具有一定的指导意义.

Thermodynamic calculation of phase equilibria in Cu-Ni-Sn ternary system

On basis of the phase equilibria and thermodynamic properties of the Cu-Ni-Sn ternary system by experiment,the thermodynamic assessment of the Cu-Ni-Sn ternary system was carried out by the CALPHAD(calculation of phase diagrams) method.The Gibbs free energies of liquid and fcc phases were described by the subregular solution model,and Gibbs free energies of the bcc phase were described by the sublattice model in order to predict the order-disorder phase transition in the bcc phase.A set of parameters describing the Gibbs energies of different phases in this system were optimized by experimental data.The calculated results agree well the experimental data.The A2/B2 ordering temperature and miscibility gap of the fcc phase can be predicted.These calculated results provide an effective guide for microstructure design of the new type Cu base practical materials with high strength and high electric conductivity.