摘要
采用锥形光头搅拌针搅拌摩擦焊接 5mm厚铝锂合金轧制板材 ,并对接头微观组织、力学性能及断裂特性进行了深入研究。结果表明 ,接头由焊核区、热机影响区和热影响区构成。焊核区在焊接过程中发生动态再结晶 ,形成细小的等轴晶晶粒 ,晶界处分布有大量的偏析相 ,热影响区组织发生粗化 ,形成粗大的板条状组织 ,前进侧热机影响区组织发生回复反应 ,后退侧热机影响区发生回复 +再结晶反应 ;硬度测试结果表明 ,接头发生软化 ,后退侧材料的软化区间和软化程度均高于前进侧 ;断口实验结果表明 ,接头断裂模式为解理断裂。
Friction stir welds (FSW) in 5mm thick, Al-Li alloy rolled sheet material have been completed. Metallurgical, hardness, tensile strength and fracture measurements have been performed. Metallurgical measurements show that there exist three different zones in FSW joints: weld nugget zone (WNZ), heat affected zone (HAZ) and thermal-mechanically affected zone (TMAZ). During welding, microstructures in WNZ occurred dynamic recrystallization and generated fine equiaxed grains, at which boundary lots of segregation microstructures appeared; microstructures in HAZ were coarsed; microstructures in advancing-side TMAZ occurred recovery; and microstructures in retreating-side TMAZ occurred recovery and recrystallization. Hardness measurements confirmed that joint was softened, and the softened degree and zone of retreating-side material was higher and wider than that of advancing-side material respectively . Fracture measurements show that the mode attributed to cleavage fracture.
出处
《中国机械工程》
EI
CAS
CSCD
北大核心
2004年第10期932-935,共4页
China Mechanical Engineering
基金
国家 8 63高技术研究发展计划资助项目( 2 0 0 2AA72 40 40 )
关键词
搅拌摩擦焊
锥形光头搅拌针
接头组织
铝锂合金
friction-stir welding
cone-shape and non-whorl pin
joint microstructure
Al-Li alloy
