(1. 西北工业大学 凝固技术国家重点实验室，陕西 西安 710072；
2. 北京钢铁研究总院 高温材料研究所，北京 100081)
摘 要: 对Ti-22Al-25Nb锻造棒材进行热处理，观察不同固溶和时效温度下合金的显微组织，研究其演化规律，并根据显微硬度评价该合金的基本性能。结果表明：合金的显微组织主要取决于热处理工艺。在980 °C以下进行固溶处理，合金的显微组织包括等轴α2相、围绕α2镶嵌的O相、板条O相以及B2基体；在980 °C以上进行固溶处理，显微组织主要包括等轴O相以及B2基体。在不同温度下时效，板条O相的尺寸及形态发生明显变化：在840 °C时效析出O相的板条粗最大，在760 °C效析出O相的板条最细小。不同温度下时效的显微硬度与热处理温度满足线性变化关系。
关键字: Ti2AlNb基合金；热处理；组织演变；显微硬度
（1. State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072, China;
2. Beijing Iron & Steel Research Institute, Beijing 100081, China）
Abstract:The forged Ti-22Al-25Nb alloy was heat treated, and the microstructures under different solution treatments and aging times were observed and the evolution was studied. The basic properties of the alloy were evaluated based on the hardness. The results show that the microstructure of the alloy is mainly depended on heat treatment schedule. Equiaxed α2 grains, rim O around α2, and equiaxed O and B2 matrix could be obtained after the samples were solution treated below 980 °C, while equiaxed α2 grains and B2 matrix existed when the samples were solution treated above 980 °C. The aging temperature is very important for the size and morphology of acicular O phase. The largest precipitate size occurred at 840 °C and the finest size was displayed at 760 °C. Experimental and statistical analysis show linear relationship between micro-hardness and the temperature of heat treatment.
Key words: Ti2AlNb based alloys; heat-treatment temperature; microstructural evolution; microhardness
