Improvement of strength-ductility combination by reactively layer-integrated steels

Abstract

Martensite-base steels can be a promising candidates for 3rd generationAHSS if the improvement of elongation is achieved. Until now, the improvement ofductility with AHSS has been carried out mainly by alloy design and microstructurecontrol. However, these attempts can be approached to the limit and we certainlyneed alternative methods. One of the possible ways will be the introduction of thelaminated structure steels. At the center, very high strength steel is located, forexample martensite phase and around this part, for increasing the elongation, veryductile component is used, for example alpha phase of steel or austenitic stainlesssteel. Thus if we control the microstructure and the layer ratio between these twophases, we can get the both the high strength and elongation.