Abstract：In this paper, to understand the plastic flow characteristics of ultra high strength and toughness steel AF1410, and build the constitutive relations of this steel, using a CSS4410 qusia-static test machine and enhanced Hopkinson pressure and tension bar technique, uniaxial compression and tension tests are both performed. True strains exceeding 20% are achieved in these tests, over the range of strain rates from 0.001/s to about 2000/s, and at initial temperatures from 100K to 600 K. The results demonstrate that: the yield stress in tension loading is lower than it in compress loading, and the difference between the compress and tension yield stresses become larger, with increasing strain rate; the plastic flow of AF1410 steel is not very sensitive to the changes of strain rate, but is relatively sensitive to temperature; the failure strain decreases with the increasing strain rate, but is not evidently affected by temperature. Finally, based on the mechanism of dislocation motion, paralleled with a systematic experimental investigation, a physical conception constitutive model is obtained for the deformation of AF1410 steel, and is evaluated by the classical J-C model. It shows that the plastic flow of AF1410 steel, in a large range of strain rates and temperatures, could be predicted by physical conception constitutive model.
2012, Vol. 33 
