Compressive Properties of Electron Beam Melted Ti–6Al–4V Porous Meshes with Different Struts Distributions

Abstract

Structural collapse caused by uneven stress distribution is one of the main failure modes of Electron Beam Melted (EBM) Ti–6Al–4V porous meshes for medical bone implantation. In this paper, two types of porous meshes with different struts distributions are fabricated by EBM methods and experimentally studied through uniaxial compression tests. The first type (mesh 1) with simplified struts distribution consists of horizontal, vertical and diagonal struts, which are connected by one node. The second type (mesh 2) has relatively complicated struts distribution with four structural nodes connected by vertical, horizontal and diagonal struts, and the inclined struts with an angle of 15° to the vertical or horizontal direction. The mechanical properties of solid Ti–6Al–4V alloy are also tested as reference for model-fitting analysis and the test results show that the EBM specimen can achieve comparable tensile strength (1186.5 MPa) and elastic modulus (106.4 GPa) as that of forging specimen. For the porous meshes, the deformation behavior of the struts along the load orientation is dominated by buckling mechanism and the deformation behavior of the struts inclined to the load orientation is governed by both buckling and bending mechanisms. The test results indicate that mesh 1 with relatively less inclined struts can achieve better compressive resistance than mesh 2 when taking the factor of mesh density into consideration. Such results indicate a simple yet meaningful view that struts distributions of the porous meshes should be designed and optimized based on their stress distribution conditions.