the formation of nano/ultrafine grained ferrite in low carbon steels containing different amounts of niobiumwas investigated using thermomechanical treatment which consisted of annealing of 85% cold rolled martensite with different parameters. the specimens were characterized by optical and scanning electron microscopy and vickers hardness test. a lamellar dislocation cell structure was formed ...

Different investigations have shown that an orientation dependence of elastic stored energy exists in cold rolled low carbon steels [i-6]. These stored energy values were estimated from Xray line broadening and electron microscope estimates of subgrain size and misorientation. The sequence of stored energy as a function of orientation was found to depend on the type of steel. In some investigat...

Calculations verify that carbon diffusion may occur during the lath martensite fomtion. Accordingly,the diffusion of int2rstitial ator ions must be taka into account nhfn martmitic transformtion is defined as a diffusionless transformation. In derivation of the kinetics equation of the ath& martensitic transfomtion,rzgardng the c a r h diffusion, i .e.the enrichment of the austenite during the ...

the effects of carbon content on the dynamic and static softening mechanisms of ti microalloy steels were investigated both in ferrite and austenite regions. the results obtained showed that recrystallization rate decreased as the percentage of carbon content was increased from 0.0035 to 0.110. this is due to the ti(cn) and tic precipitates and also the free carbon content. in the ferrite regio...

The effects of carbon content on the dynamic and static softening mechanisms of Ti microalloy steels were investigated both in ferrite and austenite regions. &#10The results obtained showed that recrystallization rate decreased as the percentage of carbon content was increased from 0.0035 to 0.110. This is due to the Ti(CN) and TiC precipitates and also the free carbon content. In the ferrite r...

In this work, dynamic mechanical properties of three high-manganese steels with TRIP/TWIP or fully TWIP characteristics are studied. High strain rate experiments in the range of true strain rates between ~500 and 1800 /s are conducted using a dynamic torsional testing setup. All the three steels show a positive strain rate sensitivity in the intermediate range of strain rates (up to 500 /s). Bu...

Point defect species and concentrations in metastable Fe-C alloys are determined using density functional theory and a constrained free-energy functional. Carbon interstitials dominate unless iron vacancies are in significant excess, whereas excess carbon causes greatly enhanced vacancy concentration. Our predictions are amenable to experimental verification; they provide a baseline for rationa...