TEM investigations on twin boundary structures of feathery crystals in aluminum alloys during Bridgman solidification

Luyan Yang, Shuangming Li, Kai Fan, Yang Li, Hong Zhong, Hengzhi Fu

科研成果: 期刊稿件文章同行评审

4 引用 (Scopus)

摘要

Feathery crystals are an ensemble of twinned dendrites, and are characterized by a unique twin boundary (TB) structure in the solidification pattern of aluminum alloys. In this work, the high-density twinned dendrites of Al-4.5 wt% Cu alloys, produced during the Bridgman solidification, have been studied using electron backscattered diffraction (EBSD) and high-resolution transmission electron microscopy (HRTEM). The experimental results showed that, after systematically decreasing the growth rate from 3000 μm/s to 1 μm/s, the TBs remained stable, while the solute field around the TBs changed significantly. According to the HRTEM results, successive stacking faults were occurred near the TBs at 1 μm/s, while slight distortion was observed around the TBs at 3000 μm/s. The composition analysis revealed an obvious solute enrichment near the TBs. Furthermore, the solute gradient profile within the TBs became smoother with the decrease in the growth speed. This is due to the more sufficient solid-state back diffusion occurring perpendicular to the twin plane after the solidification.

源语言英语
页(从-至)77-83
页数7
期刊Journal of Crystal Growth
492
DOI
出版状态已出版 - 15 6月 2018

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