Mechanical behaviors and failure modes of additive manufactured Ti6Al4V lattice structures under compressive load

Abstract

The additive manufacturing technology facilitates the formation of complex lattice structures that are difficult to be fabricated by the traditional manufacturing technologies. In order to investigate the mechanical behaviors and failure modes of Ti6Al4V lattice structures manufactured by laser powder bed fusion (L-PBF), five cell topologies such as face centered cubic with vertical struts (FCCZ), body centered cubic with vertical struts (BCCZ), face and body centered cubic with vertical struts (FBCCZ), diamond and rhombic dodecahedron (RD) were chosen. The compressive tests were performed. The deformation behaviors and failure modes of these five kinds of lattice samples were studied and compared. And stress–strain curves, the compressive strength, the elastic modulus, the specific compressive strength, and the specific energy absorption were calculated and compared. It is shown that the FBCCZ sample has the best performance on the elastic modulus and the compressive strength among these five topologies. The specific compressive strength and the specific energy absorption of the FCCZ sample are the highest, which are 131% and 116% higher than those of the diamond sample respectively. It is also found that the shear failure is the main failure mode of the FCCZ, BCCZ, FBCCZ, and RD samples. While, the diamond sample collapses layer by layer from the bottom layer to the top layer. Finite element analysis was performed and the numerical results can explain the damage evolution of all samples.