Dynamic Tensile Properties of Steels and Aluminum Alloys for a Wide Range of Strain Rates and Strain

Abstract

Through intensive analysis of the tensile stress-strain curves of a variety of steel sheets over a wide range of strain rates on the order of 10-2 ∼103 s-1 obtained by using the Sensing Block Type High Speed Material Testing System, it was confirmed that the newly-partially extended constitutive model (Tanimura-Mimura Model) is useful to simulate the dynamic stress-strain curves for the entire range of deformation reaching as far as fracture over the wide strain rate range, as long as the quasi-static stress-strain curve of the material concerned is only known in advance. Dynamic tensile properties, over the wide strain rate range and the entire strain region reaching the true fracture strain, of ten kinds of aluminum alloys, which compose of a wide strength level from a commercial pure aluminum to the extra super duralumin are systematically studied. It was cleared that the aluminum alloys belonging to the one group exhibit the positive strain rate sensitivity and the aluminum alloys belonging to another group exhibit the negative sensitivity or almost non sensitivity. It was found that the values of the true fracture strain ef are substantially not affected by the strain rates, for all the tested aluminum alloys, and are closely related to the values of the tensile strength σB whose values are obtained by the quasi-static nominal tensile stress-strain curves.