Microstructure, texture and mechanical properties of friction stir welded butt joints of 2A97 Al-Li alloy ultra-thin sheets
Microstructure, texture and mechanical properties of friction stir welded butt joints of 2A97 Al-Li alloy ultra-thin sheets
复制标题
2A97 AlLi合金超薄板搅拌摩擦焊对接接头的显微组织、织构及力学性能
DOI：
10.1016/j.jallcom.2016.08.330
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发表时间：
2017-01-25
影响因子：
6.2
通讯作者：
Liang, Pei
中科院分区：
文献类型：
--
作者：
Chen, Haiyan;Fu, Li;Liang, Pei
对1.4 mm 2A97铝锂合金超薄薄板在不同转速下进行了搅拌摩擦对接焊接。详细研究了转速对接头组织、织构和力学性能的影响。金相组织观察表明，与母材相比，接头熔核区和热机械影响区的组织有明显的细化。另外，随着转速的提高，接头中的晶粒度增大。电子背散射衍射分析表明，焊接后母材黄铜、铜和S组元的原始轧制织构强度减弱，在焊核区和接头热机械影响区有新生成的再结晶织构，如立方和立方ND组分。随着转速的增加，接头的再结晶织构强度增加，而轧制织构强度降低。随着转速的变化，由于热输入的不同，LAGBs和再结晶颗粒的比例也发生了变化。拉伸试验结果表明，随着转速从600转/分增加到1200转/分，接头的力学性能先增大后减小。接头的塑性还受组织、晶界和织构的影响。晶粒细小、LAGBs比例大、变形织构多的接头具有良好的延伸率。所有接头均以韧性或韧性-脆性断裂方式在焊缝中心失效。(C)2016爱思唯尔B.V.保留所有权利。
1.4 mm 2A97 Al-Li alloy ultra-thin sheets were welded by friction stir butt-welding at different rotational speeds. The influences of rotational speeds on microstructure, texture and mechanical properties of joints were investigated in detail. Microstructure observation shows that the grains in the nugget zone and thermo-mechanical affected zone of joints have a significant refinement compared with the base metal. In addition, the grain size in the joints increased with increasing the rotational speed. Electron backscatter diffraction analysis reveals that the intensity of the original rolling texture including Brass, Copper and S components of the base metal was weaken after welding, and there were some newly generated recrystallization textures in the nugget zone and the thermo-mechanical affected zone of joints, such as Cube and Cube ND components. Moreover, the intensity of recrystallization texture of joints increased while that of rolling texture decreased with increasing the rotational speed. With the change of rotational speed, the proportion of LAGBs and recrystallized grains changed due to the differences of heat input. Tensile test results show that the mechanical properties of joints increased firstly to a maximum and then decreased with increasing the rotational speed from 600 rpm to 1200 rpm. The ductility of joints is also affected by the microstructure, grain boundaries and textures. The joints with the small-sized grains, large proportion of LAGBs and deformation textures possess the sound elongation. All joints failed in the weld center with the toughness or toughness-brittleness fracture modes. (C) 2016 Elsevier B.V. All rights reserved.