Composition and orientation relationships of constituent particles in 3xxx aluminum alloys

Abstract

Constituent and dispersoid phases in two Direct Chill-cast 3xxx aluminum alloys after low-temperature annealing, with different silicon content have been studied. The lattice parameters, chemical composition, morphology and orientations relationships of constituent particles with regard to Al matrix have been addressed. Al(Fe,Mn) is found to be the most prominent constituent phase in the alloy with a low Si content. The orientation relationship between aluminum matrix and this phase is determined as , , which is consistent with the orientation relationships of Al(Fe,Mn) dispersoids. –Al(Fe,Mn)Si constituent particles in the Si rich alloy have been found to have various possible orientations. A gradient of Fe content is found in the –Al(Fe,Mn)Si dispersoids due to slow diffusion of Fe into dispersoids during annealing.

Keywords:

• aluminum alloys
• TEM
• electron diffraction
• orientation relationship

Acknowledgments

This work has been supported by the KMB project MoReAl financed by The Research Council of Norway, and the industrially partners Hydro and Sapa Technology. Sindre Bunkholt, NTNU, is acknowledged for help with BSE SEM imaging. Christian Simensen is acknowledged for help with particle extraction and orgainzation of the XRD measurements.