Comparison of Particle Dispersion Strengthening Estimated by Orowan Model and Ashby-Orowan Model

Abstract

In the steels with different particle dispersion, particle dispersion strengthening Δσ was theoretically estimated by Orowan model and Ashby-Orowan model. The comparison of experimental data with theoretical values proved the reasonability of Orowan model rather than Ashby-Orowan model. In Ashby-Orowan model, the line tension coefficient of dislocation is evaluated much smaller and this leads to the under-estimation of Δσ. It was also confirmed that there is no effect of grain size on 0.2% proof stress of the steels used. As a result, it is concluded that the yield stress of steels with finely dispersed particle can be explained by the addition of friction stress and particle dispersion strengthening, in the case the grain size is sufficiently larger than the particle dispersion spacing.