In-situ TEM study of the dynamic interactions between dislocations and precipitates in a Cu-Cr-Zr alloy

The dynamic interaction between precipitates and dislocations is a fundamental scientific principle for the precipitation hardening, which is hardly captured by post characterizations. In-situ tension experiments in transmission electron microscope (TEM) have been performed on the precipitation strengthened Cu-0.55 wt% Cr-0.05 wt% Zr alloy. The dynamic interaction between dislocations and Cr precipitates was recorded. The results showed that dislocations were pinned by the semi-coherent Cr precipitates and exhibited a typical intermittent gliding. The shearing mechanism was the prevalent one for the dislocations disengaging the Cr precipitates. The critical stress for shearing the Cr precipitates increased as the dislocations subsequently cut through the Cr precipitates. The in-situ tension technique in TEM could present a direct evidence of the deformation in the precipitation hardening alloys. (C) 2018 Elsevier B.V. All rights reserved.