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

Authors: Bintao Wu, Xiangfang Xu, Yugang Miao, Duanfeng Han

Abstract:

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.

Keywords: Bypass-current MIG welding-brazed, Al alloy, Ti alloy, joint characteristics, mechanical properties.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1100006

References:

[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.