T6处理后Al-Zn-Mg-Cu合金电子束焊接接头组织与织构的演变

Microstructure Evolution of T6 Treated Electron-beam Welded Al-Zn-Mg-Cu Alloy

采用扫描电镜、EBSD、透射电镜等方法研究了Al-Zn-Mg-Cu合金电子束焊接接头的微观组织特点,并分析了焊缝基体与熔合区在热处理前后织构的变化。结果表明,接头熔合区由尺寸约3～8μm的等轴细晶组成,析出相沿晶界均匀分布,经T6处理后熔合区的晶粒尺寸无明显变化,晶界变细,沿晶界分布的连续析出相溶解,残余孤立的MgZn2析出相,尺寸约1～2μm。基体主要织构为<111>和<001>丝织构,经T6(固溶时效)处理后,两种织构的含量无明显变化,织构强度略有下降,焊缝熔合区无明显的织构。

The microstructure and texture evolution of electron-beam welded Al-Zn-Mg-Cu alloy were investigated using field emission scanning electron microscopy,transmission electron microscopy and electron back-scatter diffraction（EBSD）.The results indicated that the weld nugget zone was composed of equiaxed grains with an average grain size of 3-8 μm.The second phases are mainly distributed along the grain boundaries.After T6（solution treated and aged） treatment,Most of the second phases in weld nugget were dissolved into α（Al）.The base metal exhibits the typical111 and001 fibre textures in extrusion direction,and the sharpness slightly decreased after T6 treatment.No significant texture was observed in the nugget zone.