an ultrafine grained dual phase (ufg dp) steel containing niobium was produced by a new routeutilizing simple cold-rolling and subsequent intercritical annealing of ferrite/martensite duplex startingstructures. the effects of intercritical holding time on the microstructural evolutions and mechanicalproperties were studied. the results showed that increasing intercritical holding time enhnaced ...

In this study, X-ray fractography’)-‘) technique was applied to the (GZ+~) dual phase stainless steel. Effect of the rolling direction on fatigue properties was discussed. Residual stress near the surface was measured by using X-ray diffraction method to the depth direction. Relations between X-ray parameter and fracture mechanics parameter were examined. As the result, distribution of the phas...

An ultrafine grained dual phase (UFG DP) steel containing niobium was produced by a new route utilizing simple cold-rolling and subsequent intercritical annealing of ferrite/martensite duplex starting structures. The effects of intercritical holding time on the microstructural evolutions and mechanical properties were studied. The results showed that increasing intercritical holding time enhnac...

The martensite steels produced by quenching and tempering has been used for machine structural use. Martensite in ferrite-martensite dual-phase steels (hereinafter, DP steels) also has important roll in strengthening of the automobile steel sheets. Therefore the importance of analyzing the microstructure and their mechanical properties of the martensite has been increased year by year. Many res...

Softening frequently occurs in dual-phase steels under isothermal tempering of martensite. Recently, non-isothermal tempering is implemented to decrease the softening process in dualphase steels. Here, we have discovered using high power electropulsing treatment can significantly enhance the strengthening effects via the formation of ultrafine-grained ferrite with nano-cementite particles in te...

Advanced high strength steels (AHSS) are engineered to have both high strength and enhanced formability characteristics. Yet, the formed components undergo springback due to elastic recovery after removal of the forming tools. This severely affects the dimensional accuracy of the part. Many techniques have been evolved to deal with springback. A simple approach is to design forming tools that c...

in the present research, damage mechanisms during room temperature uniaxial tensile testing of two different modern high strength dual phase steels,dp780 and dp980, were studied. detailed microstructural characterization of the strained and sectioned samples was performed by scanning electron microscopy (sem). the results revealed that interface decohesion, especially at the triple junctions of...

This work presents a unique approach for the modelling of the austenitisation of martensite in dual-phase steels within the phase-field method. Driving forces for nucleation and growth are derived from thermodynamic databases. Routines for nucleation are based on a discretisation of the classical nucleation theory. Validation is given via dilatometric experiments.