Improving interfacial properties of a laser beam welded dissimilar joint of aluminium AA6056 and titanium Ti6Al4V for aeronautical applications

Abstract

of the original manuscript:Vaidya, W.V.; Horstmann, M.; Ventzke, V.; Petrovski, B.; Kocak, M.; Kocik, R.; Tempus, G.: AbstractDissimilar welds of aluminium alloy AA6056 and titanium alloy Ti6Al4V were produced by a novel technique. AA6056 sheet was machined at one end to a U-slot shape, enabling the intake of the Ti6Al4V sheet. The Al-alloy U-slot was then butt welded by split laser beam without using a filling wire, thus making a weld by melting only the Al-alloy.Thereby the intermetallic brittle phase TiAl 3 formed at the weld interface and affected mechanical properties. As a continuation of the previous work, the joint design was modified by chamfering Ti6Al4V to reduce the formation of interfacial TiAl 3 . It is shown in this work how this seemingly insignificant joint modification has refined microstructure and increased hardness and strength. The most impressive feature was the improved resistance to fatigue crack propagation whereby the fracture type in the fusion zone of AA6056 adjacent to the weld interface changed from partially intercrystalline to completely transcrystalline. Possible metallurgical processes leading to the property improvements are discussed.

Influence of Si Coating on Interfacial Microstructure of Laser Joining of Titanium and Aluminium Alloys

“…The reaction layer can be seen with non-uniform thickness along the transverse section. In previous works 1,8 , this reaction layer has been characterized as zones with club-shaped and cellular/ serration-shaped morphologies.…”

“…The industrial demand for hybrid components has increased the necessity for joining dissimilar metallic materials 1,2 . Different techniques have been used for joining of dissimilar metals such as diffusion welding, brazing, friction stir welding, electron beam welding, and laser welding 3,4 .…”

“…In literature, different methods have been applied to inhibit the formation of brittle intermetallic compounds in the joining interface of dissimilar metals 1,11 . Researches concerning the laser joining of titanium and aluminium alloys have shown that the thick intermetallic layer can be restricted only when the titanium alloy melts during the process.…”

The Effect of Diffusion Welding Parameters on the Mechanical Properties of Titanium Alloy and Aluminum Couples

“…Vaidya et al [4] have shown in the frame of a feasibility study that the laser beam welding of Ti-6Al-4V and AA 6056 can be performed without any formation of cracks and pores, respectively. Chemical components, crystal structure, and melting points can be given as examples.…”

Generation and characterization of T40/A5754 interfaces with lasers

“…More complex geometrical configurations were also tested. For instance, Vaidya et al (2010) have also considered a butt-brazing condition, but with specifically designed u-shape AA 6056 samples, and a split-beam laser brazing to ensure a symmetrical contact with Ti6Al4V sheets. Last, Chen et al (2009) have investigated the effect of a rectangular laser spot on the dissimilar assembly of Ti6Al4V to 5A06 with V-shape groove and Al12Si eutectic filler wire.…”