A DISLOCATION-MECHANICS-BASED CONSTITUTIVE MODEL FOR DYNAMIC STRAIN AGING

摘要

Dynamic strain aging（DSA）is an important phenomenon in solute hardened metals and seri-ously affects the mechanical properties of metals.DSA is generally induced by the interaction between themoving dislocations and the mobile solute atoms.In this paper,only the interaction between moving disloca-tions and mobile solute atoms in a dislocation core area（core atmosphere）will be taken into account.To es-rablish the constitutive model which can describe the DSA phenomenon,we improved the Zerilli-Armstrongdislocation-mechanics-based thermal viscoplastic constitutive relation,and added the effect of the interactionbetween the moving dislocations and core atmosphere.Because the constitutive relation estabhshed is basedon the Zerilh-Armstrong relation,it can describe not only the DSA phenomenon,but also the mechanical be-havior of metals over a broad range of temperatures（77K～1000K）and strain rate(10-4～104 s-1).Themodel prediction for tantalum fits well with the experimental data.