Characterization of crack-free AA-7075 fabricated by laser powder bed fusion with addition of Zr50.7Cu28Al12.3Ni9 metallic glass

The inclusion of 2 wt% Zr50.7Cu28Al12.3Ni9 metallic glass (MG) powders successfully eliminated the hot cracks in AA-7075 specimens fabricated using laser powder bed fusion (LPBF). The microstructure analysis revealed a significant enhancement in grain refinement within the AA-7075/MG specimen as a result of the formation of Al3Zr precipitates. The average grain size reduced from 9.26 mu m to 1.6 mu m, and the previously coarser columnar grains transformed into finer equiaxed grains with random orientation. Moreover, the AA-7075/MG specimen demonstrated a noteworthy microhardness exceeding 160 HV. With an elongation of about 7.2%, the highest ultimate tensile stress and yield strength are 488.7 MPa and 460.8 MPa, respectively.

Automated summary

The inclusion of 2 wt% Zr50.7Cu28Al12.3Ni9 metallic glass powders successfully eliminated hot cracks in AA-7075 specimens fabricated by laser powder bed fusion. Microstructure analysis revealed significant grain refinement in the AA-7075/MG specimen due to the formation of Al3Zr precipitates. The average grain size reduced from 9.26 μm to 1.6 μm, and the previously coarser columnar grains transformed into finer equiaxed grains with random orientation.