Intermetallic phase selection during homogenization for AA6082 alloy

Abstract

The intermetallic phase selection during homogenization in a AA6082 alloy has been investigated. A short homogenization treatment at 580 {\degr}C for 4 h and a subsequent slow cooling with a rate of about 8 {\degr}C/min, rather than a conventional quick quenching into water, results in the formation of the rounded discrete Al₁₅(FeMnCr)₃Si₂ phase, which greatly suppressed the formation of the plate-shaped β-Al₅FeSi phase. Most of the Al₁₅(FeMnCr)₃Si₂ particles were observed to be very fine (about 200 nm) and homogeneously distributed in the α-Al matrix. Fine Mg₂Si particles were also observed to be located in the vicinity of Al₁₅(FeMnCr)₃Si₂ particles. Additionally, the β series precipitates (most likely β″-Mg2Si), large-scale U2-AlMgSi and B′ (type C) phases were also observed within the α-Al matrix. This investigation demonstrates that the size and distribution of the desired intermetallic phases can be influenced by suitable homogenization treatments.

Keywords:

• AA6082 alloy
• homogenization
• precipitation
• TEM

Acknowledgement

The authors gratefully acknowledge the access to the TEM facility at the Erich Schmid Institute of Materials Science of the Austrian Academy of Sciences.