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AEM Analysis of Grain Boundary Segregation and Precipitation in Al-Mg Alloys

Published online by Cambridge University Press:  02 July 2020

J.S. Vetrano
Affiliation:
Pacific Northwest National Laboratory, Richland, WA99352USA
S.M. Bruemmer
Affiliation:
Pacific Northwest National Laboratory, Richland, WA99352USA
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Extract

Magnesium is an important and common solid solution strengthening agent for aluminum alloys. It has been known for many years that Mg segregation to grain boundaries (GBs) and other structural inhomogeneities can lead to precipitation of the ² (Al3Mg2) phase during low-temperature aging. This phase is anodic with respect to the matrix so its presence degrades the stress corrosion cracking (SCC) resistance of the alloy. The details of P-phase precipitation have been studied in detail in binary Al-Mg alloys [3-5] but there is some indication that ternary elements can alter the precipitation kinetics and spatial distribution which in turn will affect SCC. Therefore we are studying the segregation and precipitation of Mg in a commercially important Al-Mg alloy which contains Mn and Cr as grain refining particles.

Specimens were prepared from a commercial 5083 heat with the composition 4.47% Mg, 0.61% Mn, 0.08% Cr, 0.09% Si, 0.21% Fe, 0.05% Cu, bal. Al (all compositions in weight percent). Following cold rolling they were given a recrystallization anneal of 10 min. @ 500°C and air cooled.

Type
Segregation and Diffusion Analysis in Materials
Copyright
Copyright © Microscopy Society of America 1997

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References

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