On the microstructure and solidification behavior of new generation additively manufactured Al-Cu-Mg-Ag-Ti-B alloys

Laser powder bed fusion (LPBF) was used to horizontally print A205 (Al-Cu-Mg-Ag-Ti-B) metal powder. The samples have been cut in various directions to analyze their phases, grain morphology, size, crystallographic orientation, and distribution of elements via X-ray diffraction (XRD), electron backscatter diffraction (EBSD), and X-ray energy dispersive spectroscopy (XEDS) in a transmission electron microscope (TEM). To monitor deformation behavior and strain distribution, several uniaxial tensile tests accompanied by digital image correlation (DIC) technique were carried out. The results showed that the as-built microstructure fully contains fine equiaxed grains with no strong preferential crystallographic orientation. The XEDS elemental maps confirmed the solute trapping phenomenon taking place during the LPBF. The stress-strain curves obtained by the uniaxial tensile testing revealed a quasi-isotropic behavior in terms of building direction; moreover, the DIC strain contour maps confirmed yield-point phenomenon and Luders bands propagation during uniaxial tensile testing. Finally, a time/temperature interdependence grain growth model was successfully applied based on no diffusion in solid and partial mixing in liquid through the entire melt pool.

Automated summary

In this study, A205 metal powder was horizontally printed using laser powder bed fusion (LPBF), and its microstructure and strain behavior were analyzed using various techniques. The results indicated the presence of fine equiaxed grains in the as-built microstructure and a quasi-isotropic behavior in terms of strain distribution.