Physical and mechanical properties of iron-aluminium-(Mn, Si) lightweight steels

Ferritic iron-aluminium and austenitic iron-manganese-aluminium-silicon all oys are showing promising physical, mechanical and technological properties , which are suitable for the development and design of new types of high st rength lightweight steels. The relatively high aluminum contents up to C-Al = 8.5 wt-% (similar to 16 at-% Al) lead to a reduction in specific weight of 10 % and more combined w ith an improvement of elastic stiffness and strength by effective solid sol ution hardening mechanisms, The multiple TRIP effect [gamma (fcc) --> epsilon (hcp(MS)) --> alpha'(bcc( MS))] in the X 5 Mn Si Al 15 3 3 steel causes high work-hardening rates and tensile strength with improved tensile ductility. With increasing manganese content up to about 22 wt-% Mn the stacking fault energy will be decreased and extensive mechanical twinning occurs and caus es extraordinary high plasticity (Twinning Induced Plasticity : TWIP effect ).