Co-Ti合金中γ相粗化动力学的实验研究和相场模拟

Experimental Research and Phase-field Simulation of Coarsening Kinetics of γ Precipitates in Co-Ti Alloys

摘要:

本研究结合实验和相场法研究了反相Co-19.7Ti合金中无序γ析出相的组织演变和粗化行为。实验和模拟结果皆表明γ析出相的形貌随时效时间增加由近球形转变成条状。γ析出相平均粒径的粗化动力学遵循r₃ = kt,可获得如下 。γ析出相平均粒径随时效时间的变化分为两个阶段,阶段I增长快速而阶段II增长速度减缓。时效温度由700_oC增至750_oC,γ相粒径分布的峰值变大以及粒径分布的宽度变窄,模拟结果与实验结果取得良好的一致性。

Abstract:

The microstructure evolution and coarsening behaviors of disordered γ phase in the inverse Co-19.7Ti alloy have been investigated by experiment and phase-field method. Both the experimental and simulated results show that the morphologies of γ particles evolved from near-circular shape to plate-like shape as the aging time increases. The coarsening kinetics for the mean particle size obeys the cube law r₃ = kt, and it can be obtained as: . There exist two distinct stages of the mean particle sizes increase versus aging time, the growth rate is dramatically larger in stage I and has a relatively slower increase in stage II. The summit value of precipitate size distributions become larger and the breadth of the distributions decrease from 700_oC to 750_oC, the simulated results reproduce well the experimental results.