Evolution and strengthening mechanism of metastable precipitates in Cu-2.0 wt% Be alloy

The gamma '' phase and the gamma' phase are metastable precipitates in Cu-2.0 wt%Be alloy, which play a key role in strengthening the alloy. This paper mainly discusses the formation process, microstructure and strengthening mechanism of these two precipitates. The structure, quantity and size of precipitates in the alloy treated at different aging temperatures were analyzed by transmission electron microscopy (TEM). The strengthening mechanism of the gamma '' phase and the gamma' phase was analyzed by theoretical calculation. The results show that with the increase of aging temperature, the size of gamma '' phase changes slightly, but the density decreases significantly, while the size and density of gamma' phase increase with the increase of aging temperature. High resolution transmission electron microscopy (HRTEM) analysis shows that the gamma '' phase is semi coherent with the matrix, so it will be cut off by dislocations. The atoms in the gamma' phase are arranged perfectly, they can't shear with dislocations, so they can be strengthened by the Orowan dislocation bypass mechanism. The strength mechanism of gamma '' phase is location shear mechanism and the strengthening mechanism of gamma' phase is Orowan bypass mechanism. (C) 2020 Elsevier B.V. All rights reserved.

Automated summary

This study mainly discusses the structure, quantity, size, and strengthening mechanisms of the gamma '' phase and gamma' phase in Cu-2.0 wt% Be alloy. With the increase of aging temperature, the characteristics of these two phases change to different degrees.