The interphase boundary effect on plastic deformation of the austenitic ferritic steel.

The influence of interphase boundary crystallography on mechanical properties has been studied in a two-phase austenitic-ferritic steel. This way done by comparing the mechanical behaviour of the steel displaying special orientation relationship (ORs) betweeen phases such as the Kurdiumov-Sachs (KS) and Nishiyama-Wassermann (NW) ones, with the steel exhibiting random misorientations. It was shown, that the steel with large fraction of special ORs exhibits lower hardness and yield strength than the steel with randomly disorientate phases. The mechanical tests performed on examples with different grain size revealed, that the hardness increases with the specific surface of interphase boundaries according to the Hall-Petch relationship.