热处理对TC11/TC17钛合金线性摩擦焊接头组织的影响

Influence of post weld heat treatment on microstructure of linear friction welded joint of TC11/TC17 titanium alloys

针对航空发动机钛合金整体叶盘的典型材料TC11和TC17进行线性摩擦焊,并对焊接接头进行热处理,用光学电镜、扫描电镜观察分析焊接接头的微观组织。结果表明:线性摩擦焊接头焊缝区为典型再结晶组织,TC11侧为马氏体组织,TC17侧为亚稳态β相组成;热处理后,TC11侧马氏体组织转化为α+β片层组织,TC17侧亚稳态β相内析出针状α相且针状α相随着热处理温度升高而长大;热处理前TC11侧热机影响区B晶界长出极细针状次生理相,随后热处理过程中极细针状次生α相消失并有细小颗粒状次生α析出,而TC17侧热机影响区在热处理前初生α相呈一定流线型,热处理后针状初生α相长大并有不同取向的α相析出。

The linear friction weld of the aeroengine materials TC11 and TC17 titanium alloys joint were processed and post weld heat treated.The optical microscopy and SEM were used to investigate the microstructure evolution of the weld area.The results show that martensite formed at the fusion line along TC11 base metal and metastable 8 were observed along TC17 base metal.After post weld heat treatment,the martensite microstructure transformed into alternating layers of equiaxed a grains and B grains.The elongated α grain precipitated from the metastable βand grown with the increase of the post heat treatment temperature.The fine elongated a precipitated from the boundary of the B grain in the thermo- mechanical affected zone along the TC11 disappeared and very small globular alpha separated out from this area after post weld heat treatment.In the thermo- mechanical affected zone along the TCI7,the streamlined primary α particles increased and α grains precipitated along different orientation.