TABLE OF CONTENTS Aluminium can be joined by most methods used for other metals including welding, brazing, soldering, bolting, riveting and adhesive bonding. Welding and brazing will be considered in some detail and the other methods only referred to briefly.
Mechanical joining by fasteners is covered by a range of engineering codes and poses no real technical problems. Aluminium alloy rivets are normally selected so that their mechanical properties closely match those of the material to be joined. Most commercial rivets are produced from one of the following alloys: 1100, 2017, 2024, 2117, 2219, 5056, 6053, 6061, and 7075. They are usually driven cold and some, e.g. 2024, if solution treated and quenched shortly before use, will gradually harden by ageing at room temperature. Alloy 2024 T4 is commonly used for aluminium bolts or screws although steel fasteners are generally cheaper. Such fasteners must be coated to prevent galvanic corrosion of the aluminium, and plating with nickel, cadmium, or zinc is generally used depending upon the corrosive environment. Under severe conditions, stainless steel fasteners are preferable.
Adhesive bonding is particularly suitable for aluminium because of the minimal need for surface preparation. For general bonding with low-strength adhesives, and in field applications, surfaces may be prepared by mechanical abrasion using wire brushes, abrasive cloths or grit or shot blasting. Where higher bond strengths are required, solvent degreasing is essential and this may need to be followed by some form of chemical treatment. This may involve immersion in an acid bath such as...
