Aluminium - advantageous joining techniques

The "primary" nature of Aluminium offers two characteristics which make for some very advantageous joining opportunities

• low melting point -> friction stir welding
• adherent oxide and low density -> adhesive bonding

Friction-stir-welding

Friction-stir-welding self-limits temperature to that when metal just turning pasty - because no longer transfers torque / rotational energy when the metal softens

Lower heat and no liquification

• avoids messing-up alloyed compositions
• limits heat-distortion

Huge bonus for Aluminium applications.

Adhesive bonding

Huge benefit for Aluminium.

Why it works so well for Aluminium

• Low density makes overlapping joint areas have no penalty
• self-healing oxide film is a good surface for the adhesive to adhere to
• the oxide is adherent to the metal, transmitting loads

Advantage of an adhesive bonded structure - particularly if the joint is planar

• testing the joint integrity (new or during outage from service) is easy