Anisotropic and temperature-dependent growth mechanism of S-phase precipitates in Al-Cu-Mg alloy in relation with GPB zones

作者：Yin, Mei-jie; Chen, Jiang-hua^*; Wang, Shuang-bao; Liu, Zi-ran; Cha, Li-mei; Duan, Shi-yun; Wu, Cui-lan

来源：Transactions of Nonferrous Metals Society of China, 2016, 26(1): 1-11.

DOI：10.1016/S1003-6326(16)64082-7

• aluminum alloy
• precipitation
• age hardening
• anisotropy
• crystal growth

By employing atomic-resolution imaging and first principles energy calculations, the growth behavior of S-phase precipitates in a high strength Al-Cu-Mg alloy was investigated. It is demonstrated that the nucleation and growth of the S-phase precipitate are rather anisotropic and temperature-dependent companying with low dimensional phase transformation. There are actually two types of Guinier-Preston (GP) zones that determine the formation mechanism of S-phase at high aging temperatures higher than 180 degrees C. One is the precursors of the S-phase itself, the other is the structural units or the precursors of the well-known Guinier-Preston-Bagaryatsky (GPB) zones. At high temperatures the later GPB zone units may form around S-phase precipitate and cease its growth in the width direction, leading to the formation of rod-like S-phase crystals; whereas at low temperatures the S-phase precipitates develop without the interference with GPB zones, resulting in S-phase precipitates with lath-like morphology.

• 出版日期2016-1
• 单位湖南大学