Investigating the Influence of Iron Content on the Microstructure and Mechanical Properties of a High Strength Al-Alloy for Additive Manufacturing

Scalmalloy®, aScalmalloy 5xxx series aluminumAluminum alloyAlloys modifiedAluminum alloys with Sc and Zr to suit additive manufacturingAdditive manufacturing needs, displays significant potential for automotiveAutomotive and aerospace applications due to its exceptional strength, low density, and resistance to corrosionCorrosion. This study investigates the impact of ironIron, a prevalent impurity in secondary aluminumAluminum, on the microstructureMicrostructure and mechanicalMechanical propertiesMechanical properties ofScalmalloy Scalmalloy® produced via laser powder bed fusionLaser powder bed fusion (PBF-LB). ThreeScalmalloy Scalmalloy® variations were examined: the original composition and two modified versions with a total Fe content of 1.8 and 3.5 wt.%. Microstructural analysis through electron microscopy and X-ray diffraction unveiled the existence of metastable Fe-rich precipitatesPrecipitates at mid-low Fe concentrations, while stable Al–Fe intermetallicsIntermetallics were observed in the variant with high Fe content. The influence of these distinct microstructuresMicrostructure was assessed using hardnessHardness and compressive tests. These assessmentsAssessment demonstrated augmented material strength at room temperature when increasing the Fe content in the composition for both as-built and peak-aged conditions. However, this enhancement diminished when the alloyAlloys containing 3.5 wt% Fe was subjected to compression at 300  \(^{\circ }\) C, resulting in outcomes comparable to the alloyAlloys with a Fe content of 1.8 wt.%. These findings contribute to an enhanced comprehension of the properties of commercial aluminumAluminum alloysAlloys containingAluminum alloys trapped impurities, which hold the potential to expand the utilization of secondary aluminumAluminum alloysAlloys withinAluminum alloys the additive manufacturingAdditive manufacturing industry.