不同焊接方法下AZ31B镁合金焊接接头组织性能研究
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摘要
针对3 mm厚的AZ31B镁合金分别进行了MIG焊、 FSW焊和CMT焊对接试验,对3种焊接方法下焊接接头的组织和力学性能进行了对比分析。结果表明, CMT焊焊接接头的抗拉强度和显微硬度比MIG焊、 FSW焊焊接接头的抗拉强度和显微硬度高;拉伸时CMT焊焊接接头断裂在母材,而MIG焊、 FSW焊焊接接头断裂在焊接接头。CMT焊有大量小颗粒状的第二相β-Al12Mg17, MIG焊焊缝金属中的β-Al12Mg17晶粒粗大,分布不均匀, FSW焊焊缝金属中没有β-Al12Mg17,但焊核区晶粒比母材晶粒细小。
The butt welding tests of AZ31B magnesium alloy with thickness of 3 mm were performed by using Metal Inertia Gas( MIG) welding, Friction Stir Welding( FSW) and Cold Metal Transfer( CMT) welding. The microstructures and mechanical properties of the welded joints under the three welding methods were compared and analyzed. The results showed that the tensile strength and micro-hardness of CMT welded joints were higher than those of MIG and FSW welded joints. The content of β-Al_(12)Mg_(17) in CMT welded joints was higher than that of MIG and FSW welded joints. The tensile fracture location of CMT welded joints was in the base metal, those of MIG and FSW welded joints was in the welded joints. There was a large number of small granular secondary β-Al_(12)Mg_(17) in CMT welded joints. The grain size of β-Al_(12)Mg_(17) in MIG welded joints was coarse and uneven distributed, and there was no β-Al_(12)Mg_(17) in FSW welded joints, but the grain of the weld nucleus was smaller than that of the parent material.
The butt welding tests of AZ31B magnesium alloy with thickness of 3 mm were performed by using Metal Inertia Gas( MIG) welding, Friction Stir Welding( FSW) and Cold Metal Transfer( CMT) welding. The microstructures and mechanical properties of the welded joints under the three welding methods were compared and analyzed. The results showed that the tensile strength and micro-hardness of CMT welded joints were higher than those of MIG and FSW welded joints. The content of β-Al_(12)Mg_(17) in CMT welded joints was higher than that of MIG and FSW welded joints. The tensile fracture location of CMT welded joints was in the base metal, those of MIG and FSW welded joints was in the welded joints. There was a large number of small granular secondary β-Al_(12)Mg_(17) in CMT welded joints. The grain size of β-Al_(12)Mg_(17) in MIG welded joints was coarse and uneven distributed, and there was no β-Al_(12)Mg_(17) in FSW welded joints, but the grain of the weld nucleus was smaller than that of the parent material.
引文
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[10]尹欣.FSW焊接AZ31镁合金板材接头组织与性能分析[J].热加工工艺,2016(13):220-222.
[2]吴国华,陈玉狮,丁文江.高性能镁合金凝固组织控制研究现状与展望[J].金属学报,2018(5):28-37.
[3]吴国华,陈玉狮,丁文江.镁合金在航空航天领域研究应用现状与展望[J].载人航天,2016,22(3):281-291.
[4]Yang M,Xiong S M and Guo Z.Effect of different solute additions on dendrite morphology and orientation selection in cast binary magnesium alloys[J].Acta Mater,2016,112:261-272.
[5]陈凌,张贤明,刘飞,等.镁合金疲劳研究现状及展望[J].重庆工商大学学报:自然科学版,2017,34(1):75-77.
[6]郭斌,张李超.Cold Metal Transfer(CMT)与CMT Advanced的异同研究[J].精密成型工程,2016,8(2):50-54.
[7]冯吉才,王亚荣,张忠典.镁合金焊接技术的研究现状及应用[J].中国有色金属学报,2005,15(2):165-178.
[8]Yonetani H.Laser-MIG hybrid welding to aluminium alloy car body shell for railway vehicles[J].Welding International,2008,22(10):701-704.
[9]马征征,王文先,许海鹰,等.AZ31B镁合金电子束焊接接头疲劳裂纹扩展速率分析[J].航空制造技术,2016(6):80-84.
[10]尹欣.FSW焊接AZ31镁合金板材接头组织与性能分析[J].热加工工艺,2016(13):220-222.