Papers by Keyword: Al-Mg-Ge

Abstract: It is known that Al-Mg-Ge alloy shows the similar precipitation sequence to Al-Mg-Si alloy, and its equilibrium phase is β-Mg₂Ge according to its phase diagram. In this study, the precipitation sequence of Al-Mg-Ge alloys containing different contents of Mg₂Ge has been investigated by hardness test, TEM and HRTEM observation to understand the effect of Mg₂Ge contents on age-hardening behavior of the alloys. The hardness of as-quenched and peak-aged samples have been improved by increasing Mg₂Ge contents. The precipitates in the peak-aged samples have been classified into some metastable phases, such as the β’-phase and parallelogram-type precipitate by HRTEM observation. The relative frequency of these precipitates in the is has been changed with Mg₂Ge contents.

Abstract: In this work, the crystal structure of the rod-shaped precipitate in aged Al -1.0 mass% Mg2Ge alloy at 523 K has been investigated by high resolution transmission electron microscopy (HRTEM), electron diffraction technique and energy dispersive X-ray spectroscopy (EDS). The rod-shaped precipitate in its alloy has showed the similar arrangement of bright dots in its HRTEM images and selected area diffraction pattern (SADP) to those of the b’-phase in Al-Mg2Si alloy. But a lattice constant of this precipitate in Al-Mg2Ge alloy was slightly larger than the b’-phase in Al-Mg2Si alloy. In addition, the new metastable phase has been found out in Al-Mg-Ge alloy.