Strain hardening and stored energy in high-Mn austenitic based low-density steel

In the present study an attempt has been made to understand the high strain hardening in austenitic low-density steel using two full field measurements of temperature and strain on the sample during tensile deformation. Based on these measurements’ evolution of energy storage during deformation was calculated. High energy storage has been attributed to the interaction between dislocation groups belonging to different slip bands and destruction of short-range order (SRO) clusters. This in turn, dictates the range of the elastic stress field of slip bands. Furthermore, weak deformation heterogeneity ensued just after yield and continued with a fixed strain pattern up to facture. This did not result in macroscopic instability but manifested as microstructural heterogeneity in the form of micro-band and nano twins at later stages of deformation. A mathematical model of energy storage based on dislocation entrapment is discussed.