[SY-C1] Thermally activated solute-drag strengthening by interstitial impurities in BCC Cr
The application of body centered cubic (BCC) refractory metals is usually limited by the low temperature brittleness, which is intrinsically linked to the limited screw dislocation mobility. We present a combined ab-initio and molecular dynamics study on the role of impurity interstitials on the dislocation mobility and the implications on the brittle-ductile transition.
The interaction forces between dislocation and impurities are computed for the kink-pair nucleation and kink-drift to predict strengthening contribution additionally to the kink-pair nucleation limited mobility below the Knee temperature. Continuum solute-drag models informed by atomistic simulations with semi-empirical potentials and with the chemically accurate ab-initio simulation are both used to predict experimental temperature regime for solute-drag strengthening. The role of dislocation core contribution compared to the elastic interaction is discussed and compared to recent nanoindentation experiments of high purity Cr with temperature-dependent hardness, activation volume and activation energies.
The interaction forces between dislocation and impurities are computed for the kink-pair nucleation and kink-drift to predict strengthening contribution additionally to the kink-pair nucleation limited mobility below the Knee temperature. Continuum solute-drag models informed by atomistic simulations with semi-empirical potentials and with the chemically accurate ab-initio simulation are both used to predict experimental temperature regime for solute-drag strengthening. The role of dislocation core contribution compared to the elastic interaction is discussed and compared to recent nanoindentation experiments of high purity Cr with temperature-dependent hardness, activation volume and activation energies.