Numerical Analysis of the Nb(C,N) Precipitation Kinetics in Microalloyed Steels

Abstract

Precipitation kinetics of Nb(C,N) in microalloyed steels is crucial for the achievement of favoured steel properties. Therefore, numerous experimental studies have been performed in the past and various theoretical models have been developed to describe Nb(C,N) precipitation. However, the experimental data is sometimes contradictory and even the thermodynamic data for NbC solubility in austenite have a large scatter. In this paper, experimental results on the Nb(C,N) and NbV(C,N) precipitation kinetics in deformed and undeformed austenite are reviewed. Based on these data and with the precipitation kinetics module of the software package MatCalc, computer simulations are performed. The predicted interfacial energy of precipitates is adjusted to match the observed kinetics. A comparison between experimental information and simulation, l.e, time -temperature -precipitation (TIP) diagrams, is drawn and discussed. The results of the computer simulations using modified interfacial energies are in good agreement with the experiments.

Concurrent Precipitation of AlN and VN in Microalloyed Steel

“…Particularly, close to the solution temperature, the effect of entropic contributions from finite interface thickness can become prominent. This behaviour of the interfacial energy has been observed in a previous work by Pudar et al 44 and treated theoretically in ref. 45.…”

Numerical Simulation of the Simultaneous Precipitation of δ and γ′ Phases in the Ni‐Base Superalloy ATI Allvac®718Plus ™

“…However, particularly, close to the solution temperature, the effect of entropic contributions from finite interface thickness can become prominent. This behavior of the interfacial energy has been observed in previous works by Pudar et al [18] in the case of Nb(C,N) as well as by Radis and Kozeschnik [19] for VN and treated theoretically in ref. [20].…”

The Precipitation Behavior of Superalloy ATI Allvac 718Plus

“…[22] However, corrections taking into account the spherical shape of the nucleus are considered as a function of the precipitate radius. [23] Entropic contributions from the finite interface thickness are taken into account by temperature-dependent correction functions ( Figure 1) as observed, [24] see also a previous study by Pudar et al [25] . The latter corrections become particularly prominent close to the solution temperature of the precipitates.…”