A model of solution strengthening of austenite by carbon and nitrogen

摘要: A quasi-chemical, pair approximation model which describes both the high temperature athermal and low thermal critical shear stress of alloy austenite strengthened by either C or N is outlined. Equilibrium local order in these dilute interstitial solutions defined terms distribution metal atoms over octahedral clusters determined a Monte Carlo method using Boltzmann acceptance criterion. An extended dislocation bounded Shockley partials intersecting cluster removes two from each replaces them nearest-neighbor atoms, while on sublattice remain undisturbed. The change number configuration pairs calculated, thereby allowing an assessment enthalpy entropy. linear function Gibbs energy. required energies pair-exchange are obtained for metal-metal comparing energy mixing calculated tetrahedral-octahedral variation, with corresponding derived experimental values recorded ThermoCalc. metal-interstitial hypothetical fcc binary alloys deduced thermodynamic data empiricalmore » solution (CALPHAD). Application illustrated calculating increase stress, at 298 K, increasing carbon nitrogen content, weight percent, Fe-12Mn-(C,N), Fe-40Ni-15Cr-(C,N), Fe-Mn-Cr-(C,N) alloys. results demonstrate well-known superior strength containing reasonable agreement measurements initial flow polycrystalline alloys.« less