WEB Effect of martensite island size on transformation induced deformation of ferrite in DP steelsThursday (24.09.2020) 15:55 - 16:10 S: Structural Materials 2 Part of:
Dual-Phase (DP) steels contain hard martensite islands embedded in a soft ferrite grain matrix, providing a good combination of strength and ductility. The formation of martensite from austenite involves a volume and shape change, causing deformation of the surrounding ferrite grains in order to accommodate the newly formed martensite. Martensite has a complex hierarchical microstructure in which the smallest structural unit is called lath. Martensite laths formed from a single prior austenite grain can have any of the 24 possible spatial orientations in space, called variants. In principle, a single martensite island can contain all 24 variants. However, if the island size is smaller than a certain threshold, only few of the possible 24 variants can be formed. This kind of variant selection within a martensite island has been studied extensively in the past but its influence on the deformation of the surrounding ferrite grains in DP steels remains unknown. The present work investigates the effect of the martensite island size on the transformation induced deformation of ferrite grains in DP steels with the help of electron backscatter diffraction (EBSD) measurements.