Fabrication of aluminum/copper clad composite using hot hydrostatic extrusion process and its material characteristics

For the present study, a hot hydrostatic extrusion process was applied to fabricate aluminum/copper (Al/Cu) clad composite at a temperature of 320degreesC. Three extrusion ratios (ER: 8.5, 19, 49) and semi-die angles (30degrees, 45degrees, 60degrees) were applied to investigate the effect of extrusion ratio and die angle in the fabrication of aluminum/copper clad composites using hot hydrostatic extrusion. Hardness distribution of the fabricated aluminum/copper clad was determined. The diffusion layer thickness at the interface between the aluminum and copper was studied by means of an FE-SEM and EDS line-profile. The results showed that for an ER of 8.5, the extrusion pressure increased as the die angle increased. On the other hand, the extrusion pressure decreased as the die angle increased for an ER of 49. In the case of an ER of 19, the extrusion pressure decreased with the die angle, but increased with further increases in the die angle. The results also showed that hardness increases with an increasing extrusion ratio. Hardness distribution was more uniform as the extrusion ratio and the die angle increased. The thickness of the diffusion layer at the interface was maximized in the case of ER = 19 and a die angle of 45degrees. The extrusion pressure was also at its lowest in the case of ER = 19 and a die angle of 45degrees. Therefore, it was concluded that the optimum extrusion condition for fabricating the aluminum/copper clad composite using hot hydrostatic extrusion was in instances when there was an ER of 19 and a die angle of 45degrees. (C) 2004 Elsevier B.V. All rights reserved.