Joining techniques for aluminium spaceframes used in automobiles

Strategies for the replacement of chromic acid anodising for the structural bonding of aluminium alloys

Adhesive joining of aluminium AA6082: The effects of resin and surface treatment

Influence of surface macroroughness on the durability of epoxide-aluminium joints

The durability of EN AW 6082-T651 aluminium alloy joints bonded with a toughened acrylic adhesive was investigated upon exposure to wet environments (humidity, water immersion and salt water immersion). Environmentally-friendly surface treatments were used to avoid hexavalent chromium. Single lap shear tests were used to determine the durability of the adhesively bonded joints. Specimens were exposed to 31% and 95% relative humidity and submerged in deionized water and 3 wt% sodium chloride solution at 25°C and 50°C, for 10, 30 and 90 days. The data collected in the experiments showed that the durability was higher for surfaces treated with γ-methacryloxypropyltrimethoxysilane (γ-MPS) and sulfo-ferric etchant (P2 etch) than other surface treatments. Both these treatments improved considerably the durability in all environments tested. The results indicate that specimens even without surface treatment maintained a significant residual strength after exposure to low humidity environment (room temperature at...

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Adhesive bonding of aluminium with structural acrylic adhesives: durability in wet environments

The interface in aluminium bonded structures can be revealed by ultramicrotomy and subsequently studied by transmission electron microscopy. By these means, the more usual surface pretreatments encountered, have been characterised in depth. A similar examination has been effected following exposure of bonded joints (floating roller peel specimens) to 85% relative humidity at 70°C. Although a drop in peel performance is noted over the exposure time, interfacial examination reveals little damage to the adhesive or adherend. Possible mechanisms for bond strength reduction are discussed: subtle undermining of the alumina film and disruption of physico-chemical bonds across the interface. Both are initiated by moisture reaching the alumina film, either passing along the interface itself or travelling through the adhesive matrix. Also considered are the effects of surface pretreatment and “oxide” penetration, by the adhesive, on durability. The effect of priming the adherend surface prior to bonding, u...

The Adhesively Bonded Aluminium Joint: The Effect of Pretreatment on Durability

The use of scanning electron microscopy (SEM), to identify areas of interest both on the substrate as well as on the adhesive fracture surface, can be augmented by revealing the adhesive/adherend interface via ultramicrotomy (1), with subsequent observation by transmission electron microscopy (TEM). This combination of techniques has already been established as a valuable tool to characterise and gain a deeper insight into the nature of substrates and interfaces within bonded joints (2, 3, 4, 5, 6).

Effects of the environment on bonded aluminium joints: an examination by electron microscopy

SummaryThe effect of surface treatment of aluminium on the resultant bond strength and its durability upon exposure to warm/humid conditions has been examined. Mechanical testing revealed the super...

Important features in the adhesive bonding of aluminium

Over the past 25–30 years much theoretical work has been carried out in an attempt to analyse the adhesive bond and hence determine the nature of the mechanisms of adhesion.

J. A. Bishopp

Papers

The Adhesively Bonded Aluminium Joint: The Effect of Pretreatment on Durability

Effects of the environment on bonded aluminium joints: an examination by electron microscopy

Important features in the adhesive bonding of aluminium

The Use of Electron Microscopy for the Analysis of the Adhesive-Adherend Interface in the Aluminium-Aluminium Bonded Joint