Strain Hardening in Fe–16Mn–10Al–0.86C–5Ni High Specific Strength Steel

This chapter report a detailed study of the strain hardening behavior of a Fe-16Mn-10Al-0.86C-5Ni high specific strength steel (HSSS) during uniaxial tensile deformation. The tensile deformation of the HSSS exhibits an initial yield-peak, followed by a transient characterized by an up-turn of the strain hardening rate. In developing various high strength steels aforementioned, a primary issue is the strain hardening capability. Strain hardening is a prerequisite for large uniform ductility. However, the mechanism of strain hardening remains an open issue for most high strength steels, because they deform very heterogeneously due to their inhomogeneous microstructures. Optical microscopy and scanning electron microscopy were used to characterize the microstructure of the HSSS before and after tensile tests. The load transfer and strain partitioning unraveled from the in situ data indicates an elasto-plastic transition, with grain-to-grain yielding until the yielding of all grains, in the order of softer and harder and finally co-deformation.