Dynamic Strain Aging Behavior in Dual Phase and Multiphase High Strength Steels

Abstract

Advanced high strength steels, especially dual and multiphase steels, exhibit interesting dynamic strain aging behavior when subjected to isothermal tests at varying strain rates. In this study, uniaxial tensile testing results are presented for two selected steels over a temperature range from 25 to 200 °C at strain rates from 5 × 10-4 to 5 × 10-1 s-1. At different temperature and strain rates, some specimens exhibit substantial dynamic strain aging (DSA) effects including negative rate sensitivity and formation of pronounced Portevin Le-Chatelier (PLC) bands resulting in inhomogeneous material deformation. Implications of DSA on performance consequences are addressed in the paper.