Strengthening due to Cr-rich precipitates in Fe-Cr alloys: Effect of temperature and precipitate composition

Molecular dynamics MD simulations were carried out to study the interaction between nanometric Cr precipitates and a 1/2{110} edge dislocation in pure Fe and Fe-9 at. % Cr random alloy. The aim of this work is to estimate the variation in the pinning strength of the Cr precipitate as a function of temperature, its chemical composition and the matrix composition in which the precipitate is embedded. The dislocation was observed to shear Cr precipitates rather than by-pass via the formation of the Orowan loop, even though a pronounced screw dipole was emerged in the reactions with the precipitates of size larger than 4.5 nm. The screw arms of the formed dipole were not observed to climb thus no point defects were left inside the sheared precipitates, irrespective of simulation temperature.