The Compressive Behavior of a Porous 316l Stainless Steel Prepared by Selective Laser Melting
B. Liu, Z.Y. Zhao, P.K. Bai, M.J. Liang and R.G. Guan
Porous 316L stainless steel powder was processed by selective laser melting (SLM) and the compressive behavior of the porous 316L stainless steel fabrications were studied. The lattices were parallel to building direction, when the porous 316L stainless steel was compressed along the building direction, the compressive stress initially increased and then decreased with increasing deformation. When the 316L stainless steel fabrications were compressed perpendicularly to the building direction, the compressive stress increased and then decreased periodically. The lattices collapsed in a layer-by-layer sequence from outside to inside. At the early stage of compressive deformation, the stress concentration occurred at the joints of the struts, forming a slip band, which promoted microcrack formation. The grain boundary was the preferred site for the microcrack pile-up through pinning the movement of the microcrack. Many microcracks accumulated near the grain boundaries, causing the eventual formation of a crack, which extended along the region of misorientation.
Keywords: Nd:YAG laser, 316L stainless steel, powder, selective laser melting (SLM), porous materials, stress, microcrack, compressive behavior