Microstructures and mechanical properties of Si and Zr modified Al–Zn–Mg–Cu alloy-A comparison between selective laser melting and spark plasma sintering

Abstract

Si and Zr modified Al–Zn–Mg–Cu alloy powders were consolidated by selective laser melting (SLM) and spark plasma sintering (SPS) routes and their microstructures as well as mechanical properties were comparatively studied. The scanning electron microscopy equipped with electron-dispersive spectroscopy was applied to characterize microstructures. Grains were characterized with X-ray diffraction and electron backscatter diffraction. Mechanical properties were characterized by tensile tests and Vickers hardness measurements. The results show that average grain sizes of the SPS and SLM processed samples are basically the same while SLM sample possesses a bimodal grain size distribution, which is different from the SPS sample with uniform grain size. Si element is randomly distributed in SPS sample in the cluster form while the Si element are uniformly distributed in SLM sample. The strength and hardness of the SLM printed sample are much higher than the SPS processed sample.