The higher strain hardening at high strain rates are due to the strong increase in the twinning propensity.

Materials Science Forum

The microstructures and the mechanical properties of two Fe-26Mn-xAl-1C steels with 8 and 10 % Al have been investigated at different strain rates. The results show that Fe-26Mn-10Al-1C steel possesses higher strength and at the same time higher ductility than Fe-26Mn-8Al-1C steel at both low and high strain rates. The strengths of the steels increase and ductility declines slightly with increasing strain rate. These observations can be attributed to the different strain hardening mechanisms acting at different strain rates. Planar slip occurs and microbands form duringthe steady state stage, whereas deformation twinning occurs in the final stage ofdeformation. The higher strain hardening at high strain rates are due to the strong increase in the twinning propensity. The strain hardening at high strain rates also depends on the adiabatic heating, causing a competition between softening and strain hardening.

The higher strain hardening at high strain rates are due to the strong increase in the twinning propensity.

Microstructural Evolution and Mechanical Behavior of Low Density Fe-Mn-Al-C Steels with High Stacking Fault Energy