Copper-clad Aluminum Research Articles

Extrusion of copper clad aluminum wire

This report describes investigation in the extrusion of copper clad aluminum wire. The variables that influence a sound clad extrusion are determined. These variables are (1) die design, (2) extrusion ratio, (3) extrusion pressure, (4) product velocity, (5) percentage copper used, and (6) ratio of flow stress of copper to aluminum. These investigations show that: (1) Successful clad extrusions may be achieved with a die angle in the range of 70° to 113°. (2) Extrusion ratios of 100:1 are possible. (3) Extrusion pressures for 15% copper performs may be written as P = 72.0 + 173 log e (A i/ A f (MPa) (4) A product velocity of about 350 fpm (1.78 m/s) seems to be the limit for sound extrusions. (5) Billets with 10% copper may be extruded with the same facility as 15% copper bars. (6) Higher extrusion ratios are possible with a core of hard drawn aluminum than with an annealed core.

Machanical properties of copper clad aluminum wire

These experiments were carried out for the production of aluminum ultra-fine wire for transistor lead by clothing it with copper and for studing its mechanical properties.The results obtained were as follows:(1) Pure aluminum ultra-fine wire produced by the method of clothing with copper was fully available for transistor lead wire, because its tensile strength was 12-13kg/mm2, its VHN was about 33, and its hardness was uniformly distributed over the whole.(2) The desirable time for process annealing of the copper clad aluminum wire should be less than 1hr at 250°C or less than 1/2hr. at 300°C when the rate of cold drawing was above 80%.(3) Intermetallic compound was formed on the boundary layer by heating for more than 2hr. at 250°C or more than 1hr. at 300°C and its hardness was higher than 500 VHN.

Measured transition from laminar to turbulent flow and subsequent growth of turbulent wakes

Abstract : Turbulent transition distances and growth of turbulent wakes behind 3/16-in. copper-clad aluminum spheres traveling through rarefied air at 18,000 to 20,000 fps are presented. The data are taken by two independent methods: twin schlieren systems (optical) and a UHF microwave cavity (electronic). The turbulent transition distances are measured to several thousands of sphere diameters at the lower pressures by both methods. Turbulent wake widths are also determined by both techniques and the 1/3 power growth rate is confirmed for these velocities. (Author)