Bonding of Al6061 by Hot Compression Forming: A Computational and Experimental Study of Interface Conditions at Bonded Surfaces

Abstract

In recent years, there has been a growing interest in composite components, which may be designed to provide enhanced mechanical and physical effective properties. One of the methods available to produce such components is joining by plastic deformation, which results in metallurgical bonding at the interface. However, the portions of the interface that are bonded and the inhomogeneity in the bonding strength achieved at the interface tend to be overlooked. In the present study, Al6061 beams were bonded, by hot compression (300–500 °C) to different degrees of reduction. The compression was followed by tensile debonding experiments and the revealed interface was microscopically characterized in order to determine the areas that were metallurgically bonded. The SEM characterization revealed that the actual bonded area is much smaller than the interface contact area. Thermo-mechanical finite element models of the compression stage were used to investigate the thermo-mechanical fields, which develop along the interface and influence the resulting bonding strength. The principal strain field patterns across the interface area were shown to be similar to the experimentally observed temperature-dependent bonding patterns. In addition, a quantitative criterion for bonding quality was implemented and shown to correlate with the experimental findings.

A Study of Interface Bond Strength Following Hot Deformation Bonding of AA6061 at Different Temperatures and Loading Rates

“…On the other hand, metallurgical bonding commonly requires a long dwelling time at the specific temperature due to the time required for diffusion processes between the layers to take place [6]. One promising method for obtaining a strong metallurgical bond in short time scales is joining by hot plastic deformation [7][8][9][10]. The mechanism of bond formation during hot plastic deformation can be divided into two parts.…”

“…Recent models even consider the hydrostatic pressure gradient that drives the atomic diffusion processes [18]. On promising criterion for assessing the quality of bond formation which takes into account both the strain, strain rate, temperature and stress is the J criterion [10,19]. The quality of the bond is determined by computing a history dependent scalar parameter J which takes the form:…”

The Influence of Time, Atmosphere and Surface Roughness on the Interface Strength and Microstructure of AA6061–AA1050 Diffusion Bonded Components

“…When the external pressure results in significant plastic deformation of the materials, the process is termed bonding by plastic forming. Such processes include hot roll bonding, hot forge bonding and co-extrusion [ 2 , 8 , 10 ]. In bonding by plastic forming, the process time is short, but the final dimensions of the composite and the different layers are hard to control due to the plastic flow of the different martials [ 2 ].…”

“…The present study focuses on determining the interface strength obtained by diffusion bonding of commercial aluminum alloy AA6061 to AA1050. The precipitation-hardenable AA6061 is favored for aerospace components and automotive parts and has superior strength relative to that of commercially pure aluminum [ 10 , 25 ]. On the other hand, pure aluminum is a soft, nonmagnetic, ductile metal that is known for its excellent corrosion resistance.…”

Hot Deformation and Microstructure Evolution of Metallic Materials

“…It was shown that panel sections can be produced from ingots with a length of 770 mm on a press with the force of 35 MN. Mittelman et al [ 24 ] studied the possibility to produce composite components by joining using plastic deformation, which results in metallurgical bonding at the interface. Beams of 6061 aluminum alloy were bonded by hot compression at temperatures of 300–500 °C to different degrees of reduction.…”