Natural Aging in Al‐Mg‐Si Alloys – A Process of Unexpected Complexity

Abstract

Abstract The natural aging behavior of pure ternary Al‐Mg‐Si alloys is investigated by measuring hardness, electrical resistivity and positron lifetime, as well as carrying out thermal analysis and atom probe microscopy. It is found that several distinct temporal stages of natural aging can be distinguished in which one of these quantities shows a characteristic behavior and that these times coincide for many of these measurements. The rate of change in the measured data is correlated with proposed solute dynamics during natural aging for both aging that takes place prior to artificial aging (natural pre‐aging) and after artificial underaging (natural secondary aging) heat treatments. Controlling factors for solute dynamics are discussed.