Al-Zn-Mg-Cu合金中一种新型Al3Zr-η′核壳颗粒的透射电子显微镜观察

Transmission Electron Microscopic Observation of a Novel Al3Zr-η′ Core-shell Particle in Al-Zn-Mg-Cu Alloy

摘要:

利用高分辨透射电子显微镜和电子衍射观察了Al-12Zn-2.4Mg-1.1Cu-0.5Ni-0.2Zr合金中的Al₃Zr-η′核壳颗粒。结果发现：Al₃Zr颗粒在合金基体中以两种形态存在,一种是与基体共格的单独存在的Al₃Zr颗粒；另外一种是作为η′析出相形核位置的核心Al₃Zr颗粒,形成了一种与基体半共格的Al₃Zr-η′核壳颗粒。该核壳颗粒的壳层由四种η′析出相变体组成。核心Al₃Zr颗粒内部的晶格变形低于单独存在的Al₃Zr颗粒,η′析出相和基体界面处存在显著的晶格应变。

Abstract:

The Al₃Zr-η′ core-shell particles were observed in the Al-12Zn-2.4Mg-1.1Cu-0.5Ni-0.2Zr alloy using high-resolution transmission electron microscopy and electron diffraction. Two types of Al₃Zr particles appeared in the Al matrix: one a standalone Al₃Zr particle coherent with the matrix and the other an as-core Al₃Zr particle acting as nucleation for η′ precipitates resulting in a core-shell particle which is semi-coherent with the matrix. The shell is composed of η′ precipitates with four variants. The strain in as-core Al₃Zr is lower than the standalone, and a considerable amount of strain exists across the interfacial regions between the η′ precipitates and the matrix.