Analyzing the effect of Fe on the microstructure and mechanical properties of a AA6008 alloy

In this study, the effect of three different levels of iron impurity on the grain structure and texture of a recrystallized AA6008 alloy after extrusion was investigated. Microstructural examination was carried out to measure the microtexture, and the results were correlated with tensile and bending mechanical properties. Results demonstrated that number density of fragmented intermetallic particles after extrusion increases with increasing Fe content. They act as the nucleation sites of new grains, therefore refining the grain structure. Increasing Fe enhances Rotated Cube texture component at the periphery and the chance for surface crack during mechanical bending test. An increment of Fe-rich intermetallics on the other hand, leads to entrapment of Si solute reducing the free Si needed for precipitation hardening proven via thermodynamic calculations. The bending formability was found to correlate with the peripheral coarse grain structure as well as intermetallic particles.