Failure modes in high strength and stiffness to weight scaffolds produced by Selective Laser Melting

Timothy B. Sercombe*, Xiaoxue Xu, V. J. Challis, Richard Green, Sheng Yue, Ziyu Zhang, Peter D. Lee

*Corresponding author for this work

Research output: Contribution to journalArticle

48 Citations (Scopus)
1 Downloads (Pure)

Abstract

The production of porous scaffold structures using additive manufacturing is becoming widespread, however a detailed understanding of the scaffold failure mechanisms is lacking. In this research, Selective Laser Melting (SLM) is used to produce Ti-6Al-4V scaffold structures consisting of a regular array of unit cells previously designed using topology optimisation. Interrupted compression testing and subsequent X-Ray Micro Tomography (XMT) characterisation is used to study the deformation and failure of the scaffolds for a range of solid fractions. Further, the XMT data of the unloaded scaffolds is used to generate meshes for finite element analysis which allowed direct comparison of desired and as built behaviour. Likely failure sites predicted from the finite element analysis compare favourably with the experimentally observed ones. Failure is initiated in areas that exhibit the greatest tensile stress, while the onset of the commonly observed layered failure occurs afterwards. The XMT of the unloaded scaffolds also highlights the inaccuracies in the SLM build process, which contributes to stress concentrations in the horizontal arms within the scaffolds. The results indicate that although the strength of the topology optimised structures is very high, further refinement in both the unit cell design and build quality would further increase the strength.

Original languageEnglish
Pages (from-to)501-508
Number of pages8
JournalMaterials and Design
Volume67
DOIs
Publication statusPublished - 15 Feb 2015

Bibliographical note

Copyright the Author(s) 2014. Version archived for private and non-commercial use with the permission of the author/s and according to publisher conditions. For further rights please contact the publisher.

Keywords

  • Selective Laser Melting
  • X-ray computed tomography
  • Titanium alloys
  • Porous material
  • Finite-element analysis

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