Non-linear mechanical response of various metals. I. Dynamic and static response to simple compression, tension and torsion in the as-received and annealed states

Abstract

The mechanical behaviour of some metals has been investigated experimentally for compressive, tensile and torsional loading cycles of about 120 and 370 mu s duration and for steady-state loading in each of the three modes of deformation. For the dynamic measurements the split Hopkinson bar technique has been used in the three modes between two rods and deformed under the action of a transient stress wave induced by dynamically loading the free end of one of the rods. The experimental results show that for the range of high strain rates investigated, the dynamic stress-strain curve is independent of strain rate in all three modes of deformation. For compression and tension, the dynamic stress levels for a given value of the strain exceed the corresponding effectively static stress levels. In marked contrast, only a comparatively small difference has been detected between the corresponding dynamic and static stress levels in torsion over a range of strain rates from approximately 10-3 to approximately 103 s-1.