基于Al元素界面调控的镁/钛激光熔钎焊接特性
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摘要
文中选用含Al量元素含量为9%(质量分数)的AZ91焊丝作为填充钎料,采用激光填丝熔钎焊的方法,利用焊丝中Al元素配合激光局部加热的特性改善非互溶不反应镁/钛之间的界面反应.探索工艺参数对焊接质量的影响规律,分析焊接接头力学性能及组织特征.结果表明,添加AZ91焊丝能够实现AZ31B镁合金/TC4钛合金的可靠连接,接头最大载荷达到1 520 N,发现焊丝中Al元素能够在激光快速加热冷却过程中偏聚到界面,并与钛侧发生冶金反应生成AlTi_3化合物,界面由较薄的反应层(2μm以下)组成,达到既实现界面冶金结合,又将反应层厚度控制在不影响接头力学性能的范围之内.
Interfacial reaction of immiscible and nonreactive Mg / Ti dissimilar joint was improved by Al element from AZ91 Mg based filler( 9 wt. %),coupled with laser local heating characteristics of laser welding-brazing method. The effect of the process parameters on weld quality was investigated. Microstructure and mechanical properties was then analyzed. The results indicated that reliable joining was achieved between Mg alloy and Ti alloy using AZ91 filler. The maximum tensile-shear force could reach 1 520 N. Segregation of Al element at the interface from filler was observed after laser fast heating and cooling,and reacted with Ti resulting in newly formed compound AlTi_3. The thickness of reaction layer was ultra-thin at approximately 2 μm. Above all,metallurgical bonding was realized while the thickness of reaction layer was kept below a certain value which did not affect the mechanical properties.
Interfacial reaction of immiscible and nonreactive Mg / Ti dissimilar joint was improved by Al element from AZ91 Mg based filler( 9 wt. %),coupled with laser local heating characteristics of laser welding-brazing method. The effect of the process parameters on weld quality was investigated. Microstructure and mechanical properties was then analyzed. The results indicated that reliable joining was achieved between Mg alloy and Ti alloy using AZ91 filler. The maximum tensile-shear force could reach 1 520 N. Segregation of Al element at the interface from filler was observed after laser fast heating and cooling,and reacted with Ti resulting in newly formed compound AlTi_3. The thickness of reaction layer was ultra-thin at approximately 2 μm. Above all,metallurgical bonding was realized while the thickness of reaction layer was kept below a certain value which did not affect the mechanical properties.
引文
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[6]Masayuki Aonuma,Kazuhiro Nakata.Effect of calcium on intermetallic compound layer at interface of calcium added magnesiumaluminum alloy and titanium joint by friction stir welding[J].Materials Science and Engineering B,2010,173:135-138.
[7]Masayuki Aonuma,Kazuhiro Nakata.Effect of alloying elements on interface microstructure of Mg-Al-Zn magnesium alloys and titanium joint by friction stir welding[J].Materials Science and Engineering B,2009,161:46-49.
[8]王涛.镁/钛异种金属冷金属过渡技术(CMT)焊接性研究[D].兰州:兰州理工大学,2013.
[9]梅张强.基于Al合金化强化的Mg/Ti电阻点焊和激光熔钎焊研究[D].武汉:湖北工业大学,2012.
[10]檀财旺,巩向涛,李俐群,等.镁/钛异种金属预置Al夹层光纤激光熔钎焊接特性[J].中国激光,2015,42(1):114-121.Tan Caiwang,Gong Xiangtao,Li Liqun,et al.Laser welding-brazing characteristics of dissimilar metals Mg/Ti with Al interlayers[J].Chinese J Lasers,2015,42(1):114-121.