Selective laser melting additive manufacturing of cancer pagurus's claw inspired bionic structures with high strength and toughness

摘要

Microstructural feature and compressive property of Cancer Pagurus's Claw were investigated. The spirally distributed pore canal tubules perpendicular to the exoskeleton surface and the typical helicoidal architecture were observed. Selective laser melting (SLM) technology, inspired by its flexible building strategy as well as track-by-track and layer-by-layer processing mode, was applied to fabricate bionic crab claw structure by using NiTi shape memory alloy powder. The influence of rotation increments and pore distribution patterns on compressive property was analyzed. The results indicated that relatively larger rotation increment tended to result in an increase of torsional rigidity and tangential force in the interfaces between adjacent tracks, thus contributing to the greater accumulated deformation. Three different pore distribution patterns were designed, all of which significantly enhanced the toughness of SLM-fabricated NiTi parts and showed the similar energy absorption capacity. However, in consideration of the reversible martensite transformation of NiTi alloys, the helically distributed pores could induce the more accumulated deformation energy to be released during the unloading process. Besides, this kind of helical distribution pattern assisted in an enhancement of in-plane isotropy, thus resulting in the more homogenous stress distribution during the loading process.