Stress-Strain Curves for Oxygen-Free High Conductivity Copper at Shear Strain Rates of up to 10 3 s -1

Abstract

Shear stress-shear strain curves for o.f.h.c. copper at room temperature have been obtained at constant shear strain rates in the range 1 to 10³s^-1, using thin walled tubular specimens in a flywheel type torsion testing machine. Results show that, for a given value of strain, the stress decreases when the rate of strain is increased. Moreover, the elastic portion of the stress-strain curve tends to disappear as the rate of strain is increased. It is postulated that these effects are due to the formation of adiabatic shear bands in the material when the given rate of strain is impressed rapidly enough. A special feature of the design of the testing machine used is the rapid application of the chosen strain rate.