(1. 中国科学院 金属研究所，沈阳 110016；2. 中航工业北京航空制造工程研究所，北京 100024)
摘 要: 研究了不同焊后热处理(PWHT)温度对Ti2AlNb合金电子束焊接(EBW)接头显微组织和显微硬度的影响。结果表明：焊态条件下，母材区是双态组织，焊缝熔合区主要是柱状B2相组织，焊接接头的显微硬度呈不均匀分布；经焊后热处理，焊缝熔合区变为网篮组织；随着热处理温度升高，熔合区中O相晶粒尺寸增大，数量减少，热影响区为双态组织，与母材区的差别在于等轴α2相边缘针状化。焊接接头的显微硬度经850、900 ℃热处理后分布均匀。
关键字: Ti2AlNb合金；电子束焊接；焊后热处理；显微组织；显微硬度
（1. Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China;
2. Research Institute of Beijing Aeronautical Manufacturing Technology, Beijing 100024, China）
Abstract:The effects of post weld heat treatment(PWHT) temperature on the microstructure and microhardness of electron beam welding(EBW) Ti2AlNb alloy joints were studied, while the welding joint was treated at different PWET temperatures. The results show that the microstructure of base metal is duplex microstructure, while the fusion zone is mainly composed of columnar B2 phase in original state，and the microhardness of the original joint is not well-distributed. After PWHT, the column crystal of fusion zone is replaced by basketweave microstructure, and with the PWHT temperature increasing, the grain size of O phase in basketweave becomes larger while the quantity of O phase becomes smaller. At the same time, the heat-affected zone remains the microstructure of base metal besides the edge of α2 phase tend needle-like. Also, after PWHT conducted at 850 ℃ and 900 ℃, the microhardness of melting joint becomes much better distributed than the original one.
Key words: Ti2AlNb alloy; electron beam welding; post weld heat treatment; microstructure; microhardness
