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 typical ＜ 111 ＞ and ＜001 ＞ fibre textures in extrusion direction, and the sharpness slightly decreased after T6 treatment. No significant texture was observed in the nugget zone.%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3～8 μm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1～2 μm.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.
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