Influence on mechanical properties of 3D printing porous tungsten by control shape and size of porous

In this paper, porous tungsten with two pore shapes, cube and triangular pyramid, were designed. The finite element analysis shows that when point, line, and surface loads are applied respectively, the stress on the cube and triangular pyramid skeleton units is uneven. When the skeleton unit is subjected to plane and line loads respectively, the stress at the supported struts is relatively small, while the stress at the unsupported struts is relatively large, causing a large amount of deformation. When the skeleton unit is subjected to a point load, its stress and deformation are both maximum at the loading point. Two types of porous tungsten with high porosity were fabricated by selective laser melting (SLM) technique, and the effects of pore shape and size on mechanical properties were investigated. The results show that the macrostructure of both these skeleton structure is not significantly different from the designed structure. Because of the hanging and sticky powders on the struts, the porosity is lower than the designed value. The tensile strength of cube skeleton with 50% and 80% porosity is 127.4 MPa and 55.8 MPa, the compressive strength is 667.1 MPa and 213 MPa, the impact toughness is 6.7641 J·cm-2 and 4.4924 J·cm-2, respectively. In addition, both have similar hardness. The compressive strength of the triangular pyramid skeleton with the same designed porosity is 231.1 MPa and 65.3 MPa, the impact toughness is 2.03 J·cm-2, and has the same hardness as the cube skeleton. The tensile and compressive fracture morphology of cube and triangular porous tungsten shows typical quasi-cleavage brittle fracture.