An Investigation of the Porosity Effects on the Mechanical Properties and the Failure Modes of Ti–6Al–4V Schwarz Primitive Structures

Porous structures fabricated using additive manufacturing demonstrate significant advantages due to their mechanical properties and light weight. However, their manufacture using selective laser melting still requires considerable research. This study investigated the mechanical properties and the failure modes of Ti–6Al–4V-built Schwarz primitive structures. Samples with five different porosities, ranging from 60 to 85%, were designed and fabricated; all samples had a length of 20 mm and consisted of 2.5-mm porous units. Compression tests were conducted to study their mechanical properties. The results show that their elastic modulus ranged from 1239.63 ± 23.69 to 3453.20 ± 105.95 MPa, and their ultimate strength ranged between 44.82 ± 0.22 and 266.31 ± 0.73 MPa. A camera used to record the failure processes revealed that Ti–6Al–4V Schwarz primitive structures exhibit brittle behaviour. Two failure modes were observed; diagonal shear was found in the 60–80% porosity samples, while unit brittle fracturing was observed in the 85% samples. This study contributes new knowledge about the design of Schwarz primitive structures and provides guidelines for choosing the appropriate porosity to meet different application requirements.