(1. 中航工业沈阳黎明航空发动机(集团)有限责任公司，沈阳 110043；
2. 中国科学院 金属研究所，沈阳 110016)
摘 要: 研究不同时效温度对Ti2AlNb基合金电子束焊接显微组织及力学性能的影响，利用金相显微镜和扫描电镜观察和分析焊接接头显微组织，并分析断口形貌。结果表明：在时效过程中，熔合区B2晶粒内析出大量的O相板条，时效温度越高，析出的板条尺寸越粗大；同时，从近热影响区到远热影响区的焊后热处理组织为网篮组织向双态组织过渡。时效处理后拉伸试样的断裂位置均为接头部位，且因时效温度升高造成细小O相板条含量减少，因而焊接接头强度下降、塑性升高。当时效温度为830 ℃时，焊件接头的室温抗拉强度σb达1 041 MPa，伸长率达到6.5%；650 ℃下σb为810 MPa，伸长率为6.5%，达到强度和塑性的最佳匹配。
关键字: Ti2AlNb基合金；电子束焊接；时效温度；焊接接头；拉伸性能
（1. AVIC Shenyang Liming Aero-engine (Group) Co., Ltd., Shenyang 110043, China;
2. Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China）
Abstract:The effects of post-weld heat treatment on the microstructure and mechanical properties of electron beam welded joints of Ti2AlNb based alloy were studied. The microstructure and fractographs were analyzed by OM and SEM. The results show that during the aging process, the laths of O phase precipitate in B2 grains in fusion zone, while the microstructure is transient microstructure from the basket-weave microstructure of near-HAZ to duplex microstructure of far-HAZ. All ruptures take place at the weld joints during tensile test after aging treatment, and with the increase of aging temperature, the strength decreases and ductility increases. When aged at 830 ℃, the tensile strengths are 1 041 and 810 MPa, respectively, and the elongations are 6.5% both at room temperature and 650 ℃, the welded joint has the best combinations of the strength and ductility.
Key words: Ti2AlNb based alloy; electron beam weld; aging temperature; welded joint; tensile properties
