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对近等温锻和梯度时效处理后的TC11/Ti-22Al-25Nb双合金焊接盘件分别进行550、600℃,时间分别为100、300、500 h的热暴露处理。用OM和TEM对热暴露后的双合金连接界面进行组织观察和相分析。结果表明:550℃热暴露100 h后,连接界面有一定区域的相贫乏带,相贫乏带随着热暴露时间的延长而逐渐消失,但600℃热暴露时组织中并没有出现相贫乏带。随着热暴露时间的增加,焊缝区条状O相数量先增加后趋于稳定,O相条粗化、增厚;热暴露500 h后条状相(α/α2)明显球化,组织趋于稳定,α2相大量溶解,连接界面逐步消失。600℃热暴露比550℃更容易得到细长的次生相。热暴露后析出相的分布比热暴露前更加均匀。
TC11 / Ti-22Al-25Nb dual-alloy welded plate after near isothermal forging and gradient aging treatment were subjected to thermal exposure at 550, 600 ℃ and time of 100, 300 and 500 h, respectively. OM and TEM were used to observe the microstructure and phase analysis of the dual alloy interface after thermal exposure. The results show that there is phase lean zone in the interface after 100 ℃ heat exposure for 100 h, and the phase lean zone disappears gradually with the increase of heat exposure time. However, phase lean zone does not appear in the heat exposure at 600 ℃. With the increase of heat exposure time, the number of O phases in the weld zone first increased and then stabilized, and the O phase coarsen and thickened. After 500 h heat exposure, the α / Tends to be stable, α2 phase a large number of dissolved, the connection interface gradually disappear. Smaller thermal phases are easily obtained at 600 ° C than at 550 ° C. The distribution of precipitated phases after heat exposure is more uniform than before exposure to heat.