Method of using copper based electrodes to spot-weld aluminium

A method for spot-welding aluminium workpieces with copper electrodes that comprises the steps of: (a) super heating copper and one or more elements X that normally have little or no solubility in copper at room temperature, such super heating being a temperature at which X is soluble in copper, X being selected from the group of Mo, Ta, V, and W, and other elements that form monostectic or peritectic phases with copper and aluminium devoid of a eutectic, X being present in an amount of 4-15% by weight of the copper; (b) rapidly cooling in the solid solution to room temperature to retain such elements in solid solution; &copy& either concurrently or subsequent to step (b), forming the solid solution as an electrode shape; and (d) passing current through the electrode shape to effect spot-welding of the aluminium workpieces. Super heating and rapid cooling may be carried out by atomising a melt of Cu and X with a pressurised gas that directs the spray onto a target for further cooling and eventual working or shaping.