Direct quantification of precipitation behavior in engineering Al-Mg-Si alloy: A study using complementary small angle neutron scattering and transmission electron microscopy

Age-hardenable Al-Mg-Si alloys are widely used in engineering applications but still lack precise, quantitative insights into their precipitation behavior. In this study, we employed small-angle neutron scattering (SANS) to systematically investigate a typical Al-Mg-Si alloy under different aging conditions, complemented by site-specific transmission electron microscopy (TEM) analysis. Our results identify a clear precipitation sequence—Guinier-Preston (GP) zones → β'' → U2 —and elucidate the underlying mechanisms through precipitation thermodynamics and kinetics. Both SANS and TEM measurements showed excellent agreement in precipitate size and volume fraction, offering valuable new perspectives on the precipitation kinetics of Al-Mg-Si alloys. • We carried out a small angle neutron scattering (SANS) study on a typical Al-Mg-Si alloy with varying aging conditions. • The SANS data and TEM analysis yielded excellent agreement in the precipitate size and volume fraction. • This consistency confirms the methodology validity and provides new insights into the precipitation kinetics of Al alloys.