铝合金中盘/片状,杆/棒状析出相的形状演变及动力学研究

Morphological development and kinetics of plate or rod shaped precipitates in aluminum alloys

摘要:

微观组织定量化研究对于建立金属材料组织和性能关系有重要意义。本文研究了可时效强化铝合金中，时效过程中析出相形状的演变和动力学过程，结合过饱和固溶体析出相变过程的经典理论、析出相生长过程的软碰撞理论和HHC理论，建立了具有盘/片状、杆/棒状析出相铝合金的析出相形状因子模型。并利用Al-Cu-Li-Zr合金T相、Al-Cu-Mg合金S相及Al-Mg-Si合金β相的析出相尺寸随时效时间变化的实验数据对模型进行验证，拟合的结果符合盘/片状、杆/棒状析出相随时效时间延长，析出相尺寸形状因子先急剧增大至极大值、再缓慢减小最终趋于稳定的一般规律，证实了模型的适用性和准确性。

Abstract:

Microstructure quantitatively analysis is significant for building the relationship between microstructure and properties, especially the ageing precipitation kinetics in aluminum alloys. A core parameter (aspect ratio) was introduced to describe the morphology change of precipitation. Aspect ratios of T1-plate precipitates in Al-Cu-Li-Zr alloys, S-plate precipitates in Al-Cu-Mg alloys and β-rod precipitates in Al-Mg-Si alloys were quantitatively analyzed. Results indicated that aspect ratios of precipitates increased at the early stage of ageing, then reached the peak and finally decreased slowly. The soft-impingement theory and HHC theory were introduced to model the ageing kinetics. Thermodynamics and kinetics parameters of different precipitates were also calculated in the model. Simulate results of different precipitates agree well with the experimental results.