热处理工艺参数对TC4+TC17线性摩擦焊接头微观组织的影响

Effects of Heat Treatment Processing Parameters on Microstructure of TC4+TC17 Linear Friction Welded Joint

在前期焊接试验参数优化基础上,对TC4+TC17钛合金进行线性摩擦焊,焊后进行不同温度的热处理,并利用光学显微镜、扫描电镜等对不同状态接头组织进行对比分析。结果表明,焊态下接头焊缝为典型动态再结晶组织,热力影响区由于热输入较小,以变形组织为主。585℃×3h热处理后焊缝TC4侧形成弥散的α+β相,细小的针状α相从亚稳态β相析出。热力影响区变形的α相在长度和宽度方向都长大,相界较焊态下更清晰;TC17侧形成细小片层状α相、针状次生α相和β相,次生针状α相沿初生α相析出。热力影响区亚稳β相分解,析出针状次生α相;热处理温度升高到685℃,接头组织的析出相长大粗化,组织趋于稳定。

Based on the parameter optimization of the pre-welding test, conducted TC4＋TC 17 titanium linear friction welding,heat treated at different temperatures after welding, and used optical microscopy, scanning electron microscopy, the joint microstructures in different status were analyzed. The results show that the RZ of as-welded joints is typical dynamic recrystallization,TMAZ is mainly deformation-based organization due to low heat input. For 585℃/3h, the TC4 RZ becomes dispersion a＋β phase, small acicular a phase precipitates from the metastable 13 phase. In TMAZ the deformed phase has grown up in the length and width, the phase boundary is more clearly than the as-welded; TC17 RZ forms small lamellar a phase, secondary acicular a phase and β phase, acicular et phase precipitates along the primary a phase. In TMAZ the metastable 13 phase decomposes, precipitates small acicular et phase; When it comes to 685 ℃, the precipitated phase of joints grow up and coarsen, the organization becomes more stable.