Quenching characteristics and microstructure of 6082 aluminum alloy

Abstract:

The microstructure and quenching characteristics of 6082 aluminum alloy were investigated via end quench test, interrupted quenching method and transmission electron microscopy (TEM). The result shows that the hardenability depth of 6082 aluminum alloy is 15-20 mm, when the cooling rate was 20℃/s, plenty of fine and dispersed β″ and a narrow PFZ were formed after artificial aging. By interrupted quenching method, when the alloys were preserved at high temperature, the precipitation of β-equilibrium phase was not obvious which retained high saturated solid solution and had small effect to aging; while in the isothermal process of medium temperature, β-equilibrium phases were formed and grew up quickly by the consumption of solute atoms nearby which made a great contribution to properties loss; When the alloys were preserved at low temperature, quench induced precipitates formed slowly but grew up with the extension of time. No matter in slow cooling or isothermal process, quench induced precipitates β is prior to nucleate on the (AlFeSi) dispersoids, which is a part reason of alloy’s high quench sensitivity.

Key words:6082 aluminum alloy; end quenched test; interrupted quench method; microstructure; precipitation free zone (PFZ); β-Mg₂Si equilibrium precipitation