Development of cancellous bone-inspired stochastic network lattice and compressive mechanical properties of PBF-LB parts

The authors have developed a cancellous bone-inspired stochastic network (CBSN), which has isotropic interconnection and orientation of the struts with stochastically determined beam lengths and bifurcation counts, without any repeated units. This study reported the effect of material, build direction of powder bed fusion using a laser-beam (PBF-LB), and compressive loading direction on mechanical properties in CBSN. A cubic model with volume fraction about 40% was generated. The diameter and mean length of struts and the mean bifurcation count in the model were analyzed. The model was manufactured with PBF-LB/stainless steel 316L and maraging steel. To investigate build direction and compressive loading direction on mechanical properties in CBSN, SUS316L specimens were manufactured in each three principal axes of the model respectively. The compressive tests were conducted in same or different direction of building. In SUS316L and MAS parts, it was found that the effect of the structure became more dominant than the material properties in the behavior after the initial yield. In SUS316L parts, the elastic modulus, offset stress, plateau stress, and energy absorption showed isotropic without dependence of build directions, which suggests that CBSN may reduce the effects of anisotropy by the PBF-LB building direction.