Identification of precipitates in 6013 aluminum alloy (Al –Mg –Si –Cu)

Transmission electron microscopy (TEM) imaging, X-ray energy-dispersive spectroscopy (EDS), and selected-area diffraction (SAD) were used with the aim of identifying the particles present in an AA 6013 alloy (Al –Mg –Si – Cu), that was developed during the last years as an alternative for the AA 6061 alloy (lower Cu content) in the automotive industry. The particles found can be classified in three different groups: silicon particles, two kinds of α(AlFeMnSi) particles, and small structural precipitates. The main interest of the AA 6013 alloy is the combined beneficial influences of medium-sized α(AlFeMnSi) dispersoids and structural precipitates. The dispersoids improve the fracture toughness by limiting grain growth. The β" phase (precursor of the β Mg2Si phase) and Q (precursor of the Q–Al Cu Mg Si quaternary phase) lead to a higher yield strength than for other 6XXX alloys.