Challenges and Latest Developments in Diffusion Bonding of High-Magnesium Aluminium Alloy (Al-5056/Al-5A06) to Stainless Steels

Abstract

The aim of this work was to investigate the challenges associated with bonding Al-Mg alloys and develop a new method for bonding these alloys to steels. During an extensive R&D project, over 80 attempts, using 11 methods, were made to bond Al-6 wt.% Mg alloy (Al-5056/Al-5A06) to two types of stainless steels (heat-resistant 1Cr18Ni9Ti and conventional 316). Wide ranges of temperature (500 °C to 580 °C), pressure (0.5 MPa to 10 MPa) and time (1 min to 2 h) were used when direct diffusion bonding of these alloys. Then, effects of using various interlayers and brazing foils were investigated. The interlayers used in this work were gallium, pure titanium, copper and aluminium foils, aluminium 6061 alloy sheets, aluminium-silicon brazing foils, zinc and zinc alloy foils as well as an active brazing foil (known as Incusil-ABA containing silver, copper, indium and titanium). Several complex and multi-stage processes, using up to 3 different interlayers in the same joint, were also developed and assessed. Examination and assessment of the bonded samples, including failed attempts, paved the way of developing new methods for bonding these dissimilar materials. A number of samples with tensile strengths from 200 MPa to 226 MPa were made by using complex combinations of 2 or 3 interlayers and triple-stage bonding cycles. The highest recorded bond strength was 226 MPa in the as-bonded condition. This value is above the measured yield strength (134 MPa) and about 93% of the measured ultimate strength (243 MPa) of the parent Al-Mg alloy after it was subjected to the same bonding cycle. Since the use of complex processes was not feasible for bonding large components, a simpler and more practical bonding cycle was also developed in the project. Using the simpler process, joints with tensile strengths around 90 MPa could be made. This article also sheds light on the difficulties associated with brazing and soldering aluminium alloys with a high magnesium content.

Fabrication Methods of Aluminium Metal Matrix Composite: A State of Review

“…On the other hand, long time sintering unconventional PM methods leads to grain growth and loss of the unique properties of composites with refined microstructure [45] 3.3 Diffusion Bonding Nikhil Bharat & P.S.C Bose [31,[42][43] says that diffusion bonding is a solid phase fabrication method used for the manufacturing of monofilament metal matrix composite. Diffusion bonding occurs as a result of diffusion of the interface atoms of the bonded materials [42,44].Matrix and reinforcements are stacked and then pressed at high temperature to complete the bonding process [48].S Venugopal, U Elaiyarasan [36-38figur] used diffusion bonding of Rolled plates of 5 mm thick AA7075 aluminium alloys using SiC papers and the most optimal parameters are found to be bonding temperature of 510 °C, bonding pressure of 13 MPa and holding time of 45 min with the desirability of 0.82.The Figure 6 shows the steps of diffusion bonding process.…”

Improved Mechanical Properties of SUS304/AA5083 Dissimilar Joint by Laser Ablation Pretreatment in Vortex- Friction Stir Lap Welding

“…The second is riveting [15,16], which can obtain high joint strength but the gas tightness is inadequate in some applications such as storage tanks. The third is solid-state welding, including friction-based welding [17,18], diffusion welding [19,20], and explosion welding [21], among which friction stir welding (FSW) is believed to be a promising weld-ing method for Al/steel dissimilar joining due to its high quality, wide adaptability, and flexibility [22,23].…”

Impact Joining of Pure Copper C1100 and Aluminum Alloy A6061-T6 Plates at Edges

“…The surface exposure and the pressure affect the welding strength [11]. Diffusion bonding was also tested at high temperatures [12][13][14]. Severe plastic deformation breaks the thin brittle oxide surface layer to press the newly created surface under high pressure.…”