Characteristics and Mechanical Properties of Bypass-Current MIG Welding-Brazed Dissimilar Al/Ti Joints

Joining of 1mm thick aluminum 6061 to titanium TC4
was conducted using Bypass-current MIG welding-brazed, and stable
welding process and good bead appearance were obtained. The Joint
profile and microstructure of Ti/Al joints were observed by optical
microscopy and SEM and then the structure of the interfacial reaction
layers were analyzed in details. It was found that the intermetallic
compound layer at the interfacial top is in the form of columnar
crystal, which is in short and dense state. A mount of AlTi were
observed at the interfacial layer near the Ti base metal while
intermetallic compound like Al3Ti, TiSi3 were formed near the Al base
metal, and the Al11Ti5 transition phase was found in the center of the
interface layer due to the uneven distribution inside the weld pool
during the welding process. Tensile test results show that the average
tensile strength of joints is up to 182.6 MPa, which reaches about
97.6% of aluminum base metal. Fracture is prone to occur in the base
metal with a certain amount of necking.

• Bintao Wu
• Xiangfang Xu
• Yugang Miao
• Duanfeng Han

• Bypass-current MIG welding-brazed
• Al alloy
• Ti alloy
• joint characteristics
• mechanical properties.

[1] Rendigs K H. Aluminium structures used in aerospace status and
prospects. Materials Science Forum, 1997, 242:11-24.
[2] Faller K, Froes FH. The use of titanium in family auto-mobiles: current
trends. Journal of Metals, 2001, 53(4):27-8.
[3] Lan Tian, Kreimeyer M, Florian W, Frank V. Laser processing of
aluminum–titanium tailored blanks. Optics and Lasers in Engineering,
2005, 43:1021-35.
[4] Lv Shixiong, Cui Qinglong, Huang Yongxian, et al. Analysis of interface
fracture behavior of arc fusion-brazed joint between titanium and
aluminum dissimilar alloys (J). Transactions of the China Welding
Institution, 2013, 34(6): 33-37.
[5] Chen YC, Nakata K. Microstructural characterization and mechanical
properties in friction stir welding of aluminum and titanium dissimilar
alloys (J). Materials & Design, 2009, 30:469-74.
[6] Yugang Miao, Bintao Wu, Xiangfang Xu, Duanfeng Han. Microstructure
and mechanical properties of bypass-current MIG welding-brazing for
magnesium / steel dissimilar metals (J). Acta Metallurigica Sinica, 2014,
(10.1007/s40195-014-0118-3).
[7] Shi Yu, Wang Zhao, Huang Jiankang, et al. Study on microstructure of
fusing-brazing joint of aluminum to galvanized steel by pulsed DE-MIG
welding (J). Transactions of the China Welding Institution, 2013, 34(5):
1-4.