Mechanical behaviour of some metals under dynamic loading

The essential behaviour of materials is characterized by the strength and deformability. To a high degree these properties are depending on the loading conditions which are determined by temperature and strain rate. A known relation between the temperature and the strain rate influence on strength is the thermal activation. In this paper the validity of the Arrhenius-equation at quasistatic and increased strain rates, higher than 10 E3 under tensile loading of a low alloyed manganese steel, of a quenched and tempered steel 4340 and a high alloyed austenitic steel is investigated. For all steels the yield strength measured at the highest strain rates corresponds with the yield strength estimated at lower temperatures and at medium strain rates. There is no indication for the change of the strength controlling yielding mechanisms like a velocity drag mechanism. In addition also UTS is governed by thermal activation. There is a good agreement of the influence of temperature and strain rat e, when the adiabatic rise of the temperature at reaching UTS is taken into account. (IFAM)