Optimizing porous Ti-6Al-4V alloys: Gradients disordered cell enhance mechanical properties and energy absorption

Abstract

Porous Ti-6Al-4V alloys produced via laser powder bed fusion (PBF-L) are highly valued for their tunable mechanical properties and excellent energy absorption, which are critical for aerospace, biomedical, and automotive applications. Achieving an optimal balance between compressive strength and energy absorption in these materials is challenging due to shear deformation in regular structured porous systems and localized stress concentrations in irregular ones. This study introduces gradient-disordered cells within an ordered matrix, enhancing both energy absorption and compressive strength while reducing shear band formation, which is typically observed in uniformly ordered structures. Through quasi-static compression testing and finite element analysis (FEA), we demonstrate that a configuration with a regularity (R) of 0.8 and two disordered layers offers the best compromise between structural integrity and energy absorption. A single disordered layer increases energy absorption by as much as 156.3 % without compromising compressive strength, highlighting the potential of gradient-disordered cellular structures to precisely tailor the mechanical properties of porous metals. When compared to uniformly ordered or fully disordered structures, these gradients deliver superior mechanical performance, offering significant advantages in structural design. However, variations in structural regularity continue to present challenges, guiding future research toward understanding the role of cell geometry and regularity in material performance.