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

作者：Zhang, Weiwei^*; Zhao, Zhihe; Fang, Jihua; He, Ping; Chao, Zhenlong; Gong, Deng; Chen, Guoqin^*; Jiang, Longtao^*

来源：Journal of Alloys and Compounds, 2021, 857: 157601.

DOI：10.1016/j.jallcom.2020.157601

• Cu-2.0 wt%Be alloy
• Metastable precipitates
• Strengthening mechanism
• Dislocation shear
• Orowan bypass mechanism

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.

• 单位
  harbin inst technol; 中国工程物理研究院; 中国科学院电工研究所