Microstructural characterization of additively manufactured multi-directional preforms and composites via X-ray micro-computed tomography

Additive manufacturing features direct and layer-by-layer fabrication and has significantly facilitated the microstructural design and fabrication of a wide range of highly complex parts. To enable the application of additive manufacturing in major industries and composites, it is necessary to evaluate the microstructural features of additively manufactured parts. Among the various advanced characterization techniques, X-ray micro-computed tomography (mu-CT) showed unique advantages as a high resolution, nondestructive and 3D visualization and measurement technique for material characterization. In the research reported in this article, we have fabricated an array of multi-directional preforms and composites and have characterized their microstructural features via X-ray mu-CT. First, a solid specimen as well as 3D orthogonal and 3D braided preforms have been fabricated using fused filament fabrication (FFF) and inspected with X-ray mu-CT Then, the fabricated preforms have been infused with silicone matrix and the multi-directional preforms and composites have been tested in compression at different strain levels, to reveal their damage evolution under compressive loading. The preliminary effort made in this research demonstrates the feasibility of characterizing microstructure of additively manufactured parts via X-ray mu-CT technique and enables an investigation of the microstructural features and damage evolution of multi-directional preforms and composites. (C) 2016 Elsevier Ltd. All rights reserved.