交变温度场下Ni75AlxV25-x合金筏化的微观相场模拟

Microscopic Phase-Field Simulation for Rafting of Ni75AlxV25-x Alloys in the Cyclic Temperature Field

摘要:

基于三元体系的微观相场动力学模型，研究了交变温度场下Ni75AlxV25-x合金组织的筏化现象以及温度、成分改变时各相体积分数的变化。结果表明：交变温度下DO22有序相具有显著筏化趋势；Al含量较高时，L12有序相在弹性软方向上具有明显的筏化现象；当交变高温温度一定时，与恒定温度场时效后的合金相比，L12有序相的体积分数平衡值稍高，随着时效的进行和交变高温温度的升高，L12有序相的体积分数平衡值呈现缓慢升高的趋势

Abstract:

Based on the microscopic phase-field kinetic model for ternary alloys, rafting of the microstructure of Ni75AlxV25-x alloys in the cyclic temperature field and the diversification of the volume fraction with the temperature and composition change were investigated. The results show that the DO22 phase is rafted obviously in the cyclic temperature field; the L12 phase is rafted obviously on the elastic soft direction when the Al content is higher. When the temperature of the cyclic temperature field is up to a certain value, the equilibrium volume fraction value of the L12 phase is higher than that in the constant temperature field; the equilibrium volume fraction value of the L12 phase increases slowly with the aging proceeding and the temperature of the cyclic temperature field increasing