MICROSTRUCTURE AND STRENGTH OF Cu-Fe IN SITU COMPOSITES AFTER VERY HIGH DRAWING STRAINS

摘要

Composites consisting of a Cu matrix and a body centred cubic (b.c.c.) phase of fibre morphology have been prepared from rapidly-solidified powders or spray-deposited billets by extrusion and heavy cold drawing. During deformation the b.c.c, phase elongates into ribbons and the microstructure refines, leading to large increases of tensile stresses. The rapid solidification techniques give a fine initial microstructure so that significantly increased strength is observed after a relatively small amount of cold working, whilst after heavy working the material becomes very strong with the microstructure reaching nanoscale dimensions.