PLASTICITY OF IRON SINGLE CRYSTALS

Abstract

Results accumulated in the past four years on the plastic deformation of iron single crystals are summarized.The work-hardening behavior of iron single crystals depends very much on orientation and temperature. At room temperature, three-stage hardening was observed for single-slip orientations. The work-hardening rates in stages I and II were correlated with the extent of localized secondary slip.Latent hardening was observed in iron crystals. The latent-hardening ratio is about 1.3 and is relatively independent of temperature and choice of latent system.The yield stress of iron single crystals is very dependent on temperature and is also sensitive to orientation at low temperatures and to interstitial content at all temperatures. By adding interstitials to purified crystals, the athermal portion of the flow stress of iron is raised, but its temperature dependence is not altered. Crystals oriented for single slip on the (101) and (112) planes have different temperature dependences of the proportional limit. Similar but small differences in this temperature dependence of proportional limits were observed in crystals oriented for single, double, and multiple slip on {112} planes. These results are explained on the basis of a Peierls mechanism.