Combining HAADF STEM tomography and electron diffraction for studies of α-Al(Fe,Mn)Si dispersoids in 3xxx aluminium alloys

Abstract

A new methodology to study the precipitation crystallography of dispersoids in an Al matrix is proposed. By combining high angle annular dark field tomography and electron diffraction studies, the three-dimensional morphology, orientation relationship (OR) with Al matrix and habit planes of the dispersoids can be achieved simultaneously. This approach has been applied to investigate the -Al(Mn,Fe)Si dispersoids precipitated in an AA3xxx alloy. Most dispersoids have a plate-shaped morphology after low-temperature homogenization at 450C. The largest proportion of the dispersoids follows the previously described OR with the Al matrix . Two plate-shaped dispersoids have been studied in detail. The dispersoid following the commonly observed orientation had habit planes . The dispersoid not following the commonly observed OR had habit planes , with (OR) , .

Keywords:

• aluminium alloys
• electron diffraction
• tomography
• orientation relationship

Notes

Supplemental data for this article can be accessed here http://dx.doi.org/10.1080/14786435.2015.1006294.

Additional information

Funding

This work was supported by the KMB project MoReAl financed by The Research Council of Norway, and the industrial partners Hydro and Sapa Technology.