Effect of electropulsation treatment and subsequent hot-working on grain-size of Cu-Al-Ni alloys

Abstract
Electropulsation treatment has been used in refining grain-size and modifying structure of polycrystalline Cu-AI-Ni alloys. The grain-size and its stability are mainly studied after various hot-working. It is found that the electropulsation is an effective way of refining the grain-size and improving the solidification structure of the alloy. By adjusting the pulsation parameters, the macrostructure of the ingot is changed into a nearly equiaxied fine-grain region. In further hot working and heat-treatment such as annealing, forging and solution treatment, the grain-size of the alloy has a tendency to grow, which diminishes the refining effect of pulsation treatment. However, if hot-extrusion is utilized to replace initial forging, die structure of the alloy can be further improved and the grain-size of the alloy is remarkably refined. The hot-extrusion of the pulsationed alloy is of vital importance to the structure of the finished products, since after hot-extrusion, further hot-forging does not bring the fast growth of grains.