Mechanical Properties of Bulk Ultrafine‐Grained Copper

Abstract

Bulk Cu with high strength and appreciable tensile ductility has been developed by refining the grain size down to nanocrystalline/ultrafine‐range by appropriate combination of conventional rolling at cryogenic condition and controlled recrystallization. The grain size has been estimated at different stages of deformation and annealing by carrying out x‐ray diffraction analysis. Mechanical properties of the samples have been determined by hardness measurement and tensile testing. The results have indicated that mechanical property of the bulk nanocrystalline/ultrafine‐grained Cu is strongly dependent on the grain size. Electrical performance of the Cu samples determined by conductivity measurement has been suitably correlated with the grain size. It is suggested that conventional rolling at subzero temperature followed by controlled recrystallization may be utilized as an effective method for development of bulk Cu, with two‐fold improvement in yield strength in comparison to its coarse grained counterpart, and a ductility value much higher than that usually observed in the nanocrystalline microstructures.

Keywords:

• ultrafine‐grained copper
• tensile properties
• deformation behavior
• sub‐zero rolling
• recrystallization