Compressive behavior and property prediction of gradient cellular structures fabricated by selective laser melting

Triply periodic minimal surface (TPMS) structures are ideal for applications such as lightweight and bone implantation. Compared with uniform structures, functionally graded cellular materials (FGCMs) are more attractive due to their diverse performance and excellent adaptability to actual requirements. A series of uniform cellular structures including Primitive and Gyroid type are designed and manufactured by selective laser melting (SLM) to understand the morphology, geometry characteristics as well as mechanical properties. Then, the transversely and longitudinally graded cellular structures are proposed to understand its relation to uniform cellular structures. The results show that the actual porosity of cellular structures is slightly lower than the designed, with a small deviation of 2.2%- 3.7%. The elastic modulus and yield strength of uniform cellular structures decrease gradually with increase of porosity. The mechanical properties of uniform cellular structures relative to solid counterparts can be predicted from Gibson-Ashby equations. The porosity gradient TPMS structures are found the mechanical accumulation of uniform cellular substructures. The mechanical properties of gradient TPMS structures can be modelled by composite theories.