Pentamode metamaterials (PMs) have uncoupled relative density and mechanical properties

which have potential applications in the field of special acoustic equipments and biological implants. Selective laser melting (SLM) technology has the ability to form complex and fifine lattice metamaterials

which can achieve customized stiffffness

controllable cell topology

cell size and porosity. In this work

nickel-titanium shape memory alloy (NiTi SMA) powder was used to fabricate pentamode metamaterials with difffferent topological shapes by selective laser melting. The observation results of micro-morphology show that the nickel-titanium based pentamode metamaterials formed by SLM has good manufacturing fifidelity. The fifinite element simulation is used to predict the stress distribution in the compression process of the pentamode metamaterial

and it is found that the stress is concentrated in the joint of the struts. The experimental results of compression mechanics show that the strength of NiTi based pentamode metamaterial increases with the increase of relative density. By establishing the mathematical models of relative density

relative modulus and strength

the mechanical properties of pentamode metamaterials with difffferent relative densities can be well predicted.