Influence of unit cell pose on the mechanical properties of Ti6Al4V lattice structures manufactured by selective laser melting

Reducing the relative quality of lattice materials is a key factor in expanding their scope of application. In this work, an octahedral structure is rotated about the stress-loading axis; the structure mirrors and symmetrically forms variable pose octahedral structures (VPOSs). Experimental samples of Ti6Al4V, including both VPOS and a body-centered cubic (BCC) octahedral model, are prepared by selective laser melting (SLM). The influence of pose (theta) on the relative density of the lattice structures is evaluated analytically. The mechanical response and specific energy absorption (SEA) of these structures under compression are investigated. Compared with the experimental BCC data, the relative density of the VPOS samples is reduced, and their SEA values are improved. The mechanical properties of the VPOSs in the z and y directions are optimized when theta = 43 degrees. When theta = 10 degrees, the z-direction SEA is maximum (similar to 2.4 times the BCC value). Among the various Ti6Al4V octahedral lattice structures, the structure with theta = 43 degrees exhibits the best mechanical properties at unit density. This study demonstrates that the performance of lattice structures can be improved to different degrees by varying the unit cell pose.