Tensile and Fatigue Behaviors of Additively Manufactured AlSi10Mg:
Effect of Solutionizing and Aging Heat Treatments
Abstract
The effects of various heat treatments on the microstructure and
mechanical properties of laser beam powder bed fused AlSi10Mg were
investigated. Specimens were solutionized at three different
temperatures of 425, 475 and 525 °C followed by natural aging (T4) prior
to microstructural and mechanical characterization. In addition, the
effect of aging was studied by artificially aging (i.e., T7) some of the
solutionized specimens at 165 °C. Solutionizing at all temperatures was
observed to fully dissolve the additive manufacturing (AM) induced
dendritic microstructure, leaving bulky Si and needle-shaped β-AlFeSi
precipitates in the grain interiors and boundaries. Tensile results
revealed that T4 specimens exhibited more ductility, while T7 specimens
showed substantially higher strengths with slightly reduced ductility.
Interestingly, no significant effect of heat treatment on strain-life
fatigue behavior was observed. Fractography found the Si-particles to be
responsible for tensile fracture, while AM volumetric defects were the
main initiators of fatigue cracks.