(1. 西北工业大学 凝固技术国家重点实验室，西安 710072；
2. 北京钢铁研究总院，北京 100081)
摘 要: 研究了Ti-22Al-25Nb合金中第二相颗粒对于B2晶粒长大的抑制作用。采用图像分析软件统计了不同加热温度和时间下的B2晶粒尺寸。总体上来说，B2晶粒尺寸随着加热温度的升高和时间的延长而增加。随着加热时间的延长，原先的α2颗粒逐渐溶解到B2基体里面，α2颗粒的数量减少，这导致颗粒的钉轧作用减弱。当保温时间少于2 h，加热温度从1 000 ℃升高到1 040 ℃时，B2晶粒的平均长大值分别为24、35和53 μm/h。而当加热时间超过2 h后，B2晶粒的长大速度明显减慢。Zener模型可以很好地预测第二相颗粒作用下的晶粒长大行为，其预测模型为R=4/9(r/fv)。
关键字: Ti2AlNb；显微组织；晶粒长大；钉轧作用；模型
（1. State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072, China;
2. Beijing Iron and steel Research Institute, Beijing 100081, China）
Abstract:The pinning effect of the second-phase particles on B2 grain growth of Ti-22Al-25Nb was investigated. The grain sizes at different heat treatment temperatures and holding time were obtained by means of the image analysis software. Generally, the grain size increases with the heating temperature and time increasing. The α2 particles will be gradually dissolved and transformed to B2 phase as the holding time increases at a certain temperature, leading to the decreasing of the pinning effect of α2 particles. The B2 grains grow up at 24, 35 and 53 μm/h in average as the temperature increases from 1 000 ℃ to 1 040 ℃ with the holding time below 2 h; while after 2 h, the grains grow up slowly. Zener’s equation is a reliable model to predict the B2 grain growth and the prediction model can be expressed by R=4/9(r/fv).
Key words: Ti2AlNb; microstructure; grain growth; pinning effect; model
