Application of a new model to the interphase precipitation reaction in vanadium steels

As-cast mechanical properties of vanadium/niobium microalloyed steels

“…Many TEM studies on microalloyed steels have demonstrated the formation of interphase precipitation of carbonitrides in the form of sheets which are parallel to the ␥/␣ interface. In addition, they have proved that the precipitates in the sheets have B-N orientation relationship with ferrite [19][20][21][22][23][24]. Hence, it can be concluded that the sheets depicted in Fig.…”

“…interphase precipitation, and from supersaturated ferritic matrix, i.e. random precipitation, play a major role in precipitation hardening in microalloyed steels [19][20][21][22][23][24]. As a result, the increase observed in the strength of the microalloyed heats can be attributed to the precipitation of fine-scale carbonitrides in the form of interphase (Fig.…”

Effects of Ferrite Growth Rate on Interphase Boundary Precipitation in V Microalloyed Steels

“…Todd et al [6][7][8] proposed the prediction model based on the solute-drag nucleation model. In their model, the intersheet spacing is determined by the width of diffusion layer of V. On the other hand, the model proposed by Rios 9) is based on the ledge mechanism.…”

“…[6][7][8][9][10][11][12][13] In the model proposed by Todd et al, [6][7][8] the intersheet spacing of interphase boundary precipitation is determined by the diffusion profile of the solute concentration in the front of the growing interphase boundary of a "pseudophase", as which they defined the sheet region. Contrarily Rios 9) considered the intersheet spacing in vanadium steels is decided by the balance between vanadium flux entering into "vanadium diffusion zone" through the austenite/ferrite interface at the front of ledge and vanadium amount included in interphase precipitates which was formed at the neighbor of vanadium diffusion zone.…”

Interphase Precipitation – An Interfacial Segregation Model

“…3) Many models have been proposed in attempt to explain and provide guidance for the exploitation of interphase precipitation. [8][9][10][11][12][13][14][15][16] One branch of models including the studies of Rios,10,11) Lagneborg and Zajac 12) proposed ledge based models, using the diffusion of micro-alloying elements such as V to compute the distance when solute concentration enabled nucleation of the precipitates. Okamoto and Ågren built upon these studies incorporating the effect of solute drag in the case of an Nb microalloyed steel.…”