Investigation of pre-existing particles in Al 5083 alloys

Pre-existing particles formed in Al 5083 alloys (H131 and H116) have been investigated using scanning transmission electron microscopy(STEM), energy-dispersive X-ray spectroscopy(EDS), atom probe tomography (APT), and small angle neutron scattering (SANS). Three types of pre-existing particles, Al6Mn, Mg2Si, and alpha-Al(Mn,Fe)Si, were observed in Al 5083 alloys, and their relative fraction was obtained from EDS results. The average size, number density, and interfacial area of pre-existing particle were calculated using STEM and SANS results. In addition, an extra layer rich in Mg and Si was found on a pre-existing Mg2Si particle, and an Al6Mn layer was identified on an alpha-Al(Mn,Fe)Si particle. Thermodynamic calculations were also applied to investigate the possible pre-existing particles formed in the alloys, which can be used to explain the extra layers formed on Mg2Si and alpha-Al(Mn,Fe)Si particles. (C) 2017 Elsevier B.V. All rights reserved.