Abstract: A method of producing bellows from metal alloys comprises reeling a tubular workpiece to reduce the wall thickness thereof under volume deformation, heating the reeled tubular workpiece at a rate of 100 to 800.degree. C. per sec by passing electric current therethrough up to a temperature exceeding the recrystallization of the alloys, and cooling the heated tubular workpiece. Thereafter, the tubular workpiece wall is locally deformed in a transverse direction to form annular grooves thereon, and then corrugations are made by plastically deforming the tubular workpiece under axial compression and under excessive internal pressure produced therein. Thus obtained corrugated workpiece is heated by passing electric current therethrough at a rate of 25 to 100.degree. per sec up to a temperature at which finely dispersed phases of the alloy precipitate at a maximum rate, and held at the above temperature for 0.5 to 120 min.

Abstract: A copper-based alloy also contains aluminium and hafnium expressed as weight percentages:Aluminium 0.01 to 1Hafnium 0.005 to 1Copper the balance.The alloy may also contain 0.01 to 1% by weight of titanium.The proposed alloy combines high electrical conductivity which is 75 to 99% of that of copper, together with increased mechanical strength at room temperature and an ability to maintain its high strength during shorter long term exposure to temperatures.