TEM Observation for Precipitates Structure of Al-1.0Mass%Mg2Ge Alloys Aged at 473K

It is known that Al-Mg-Ge alloys show a similar precipitation sequence to that of Al-Mg-Si alloys, and that ther equilibrium phase is β-Mg2Ge according to the phase diagram. In this study, the precipitation sequence and age-hardening behavior of Al-1.0mass%Mg2Ge alloys has been investigated by hardness test, write out in full first time used TEM and HRTEM observations on.The hardness curves showed no big difference between peak values hardness for samples aged at 423, 473 and 523K. The precipitates in the peak-aged samples have been classified as some metastable phases, such as the β’-phase and parallelogram-type precipitates by HRTEM observation. The large precipitates are similar to the A-type precipitate in the Al-Mg-Si alloy with excess Si.

HRTEM Observation of Age-Precipitation in Mg-2.9at.% Alloys

The magnesium alloy containing rare earth element is known to show good heat resistance. In this study, Mg-Y, Mg-Gd and Mg-Gd-Y alloys including the same total amount of solute elements have been investigated to clarified the effect of the Y atom on age-hardening and precipitation using HRTEM, SAED technique and HRTEM simulation. The diffuse scattering by SAED was obtained in as-quenched condition in all alloys. In the specimen at as-quenched condition, the row contrasts consisted of bright and dark dots lying on the {100}Mgplanes, which were considered to mono-layer were observed by HRTEM.

Hrtem Observation of the Precipitates in Cu and Ag Added Al-Mg-Si Alloys

It has been known that Cu- and Ag-added Al-1.0mass%Mg2Si alloys (Al-Mg-Si-Cu alloy and Al-Mg-Si-Ag alloy) have higher hardness and elongation than those of Al-1.0mass%Mg2Si alloy. In this study, the aging behaviour of Al-Mg-Si-Cu alloy, Al-Mg-Si-Ag alloy and (Cu+Ag)-addition Al -1.0 mass% Mg2Si alloy has been investigated by hardness test and TEM observation. The Al-Mg-Si-Cu-Ag alloy has the fastest age-hardening rate in the early aging period and the finest microstructure at the peak hardness among three alloys. Therefore the microstructure of the precipitate in Al-Mg-Si-Cu-Ag alloy has been investigated by HRTEM observation to understand the effect of Cu and Ag addition on aging precipitation.