Compression deformation behavior of Ti-6A1-4V alloy with cellular structures fabricated by electron beam melting

Ti-6A1-4V alloy with two kinds of open cellular structures of stochastic foam and reticulated mesh was fabricated by additive manufacturing (AM) using electron beam melting (EBM), and microstructure and mechanical properties of these samples with high porosity in the range of 62%similar to 92% were investigated. Optical observations found that the cell struts and ligaments consist of primary alpha' martensite. These cellular structures have comparable compressive strength (4 similar to 113 MPa) and elastic modulus (0.2 similar to 6.3 GPa) to those of trabecular and cortical bone. The regular mesh structures exhibit higher specific strength than other reported metallic foams under the condition of identical specific stiffness. During the compression, these EBM samples have a brittle response and undergo catastrophic failure after forming crush band at their peak loading. These bands have identical angle of similar to 45 degrees with compression axis for the regular reticulated meshes and such failure phenomenon was explained by considering the cell structure. Relative strength and density follow a linear relation as described by the well-known Gibson-Ashby model but its exponential factor is similar to 2.2, which is relative higher than the idea value of 1.5 derived from the model. (c) 2012 Elsevier Ltd. All rights reserved.