Superior compressive performance of selective laser melted Al-8.3Fe-1.3V-1.8Si alloy lattice

Selective laser melted (SLM) Al-8.3Fe-1.3V-1.8Si aluminum alloy presents superior mechanical properties. The objective of this study was to investigate the effects of unit cell design on the uniaxial compressive properties and fracture mechanism of SLM Al-8.3Fe-1.3V-1.8Si lattice. The results show that the compressive strengths of the body-centered cubic (BCC) and face-centered cubic with Z-axis strut (FCCZ) samples were 109 MPa and 298 MPa, respectively. In the FCCZ sample, the strain first concentrated at the interconnections between the Z-axis and diagonal struts and gradually extended into the Z-axis strut. The Z-axis struts could effectively endure the compressive stress and then buckle without cracking, resulting in the high and wide first maximum compressive peak up to 25 % strain. Due to the large first maximum compressive peak and the stable stress in the plateau and densification areas, the energy absorption at 50 % strain of the FCCZ sample was as high as 86 ± 3 MJ/m³. Furthermore, the SLM Al-8.3Fe-1.3V-1.8Si lattice with the FCCZ unit cell exhibited better compressive strength and energy absorption than those of SLM Ti-based metallic lattices in the literature with comparable relative densities. Thus, SLM Al-8.3Fe-1.3V-1.8Si lattice is a promising candidate for high-strength and lightweight applications. Furthermore, this study is the first to propose that the digital image correction (DIC) strain maps be analyzed in more than just the loading direction alone, which has helped in the clear identification of the deformation/fracture mechanism and lattice design of SLM alloy lattices.