Investigation of compatibility between design and additively manufactured parts of functionally graded porous structures

Abstract

In this study, deviations for the porosity level of the Ti-6Al-4V functionally graded porous structures for three different cell structures were investigated. For this purpose, functionally graded porous structures are designed and produced by selective laser melting (SLM). It is also aimed to investigate the effects of unit cell structure, unit cell size, and column (strut) thickness on the porosity deviation level. The specimens were scanned at micro-computed tomography (micro-CT) to determine the structure dimensions after production. According to the results obtained from micro-CT, an average increase of 150-300 μm was observed on the column thicknesses of all functionally graded porous structures. It has been observed that the horizontal columns of cubic and octagonal structures have sagging due to metal melting during production. It has been determined that the porosity of the manufactured parts was deviated between 5.71%-10.54% for cubic, 8.59%-12.39% for octahedroid, and 13%-16.49% for diamond structures compared to the design values.