A comparison has been made between the recrystallization behaviour of the same composition copper plates fabricated from the ingots of cast metal and powder-metallurgy metal.
Using the hardness and X-ray analysis combined with metallographic studies, it has been shown that
the two materials recrystallize in different manners. In primary recry-stallization, at cold reduction less than 50 per cent, powder-metallurgy copper recrystal-lized at lower temperature than cast metal. While, more than 50 per cent, powder-meta-llurgy metal recrystallized at higher temperature than cast metal. Therefore, powder-meta-llurgy metal exhibits good resistance to softening in heavy working. In secondary recrystallization, cast copper began coarsening at lower temperature than powder-metal-lurgy metal, but, after completion of secondary recrystallization, powder-metallurgy metal presented larger grain than cast metal.
In relatively porous specimen, powder-metallurgy metal exhibited normal, continuous and slight grain growth without secondary recrystallization.