Evolution of internal pores within AlSi10Mg manufactured by laser powder bed fusion under tension: As-built and heat treated conditions

Research output: Contribution to journalArticlepeer-review

Authors

  • James C. Hastie
  • Joachim Koelblin
  • Mehmet E. Kartal
  • Moataz Attallah
  • Rafael Martinez

Colleges, School and Institutes

External organisations

  • University of Aberdeen
  • University of Birmingham

Abstract

The optimisation of processing parameters to produce high densification AlSi10Mg parts by laser powder bed fusion (LPBF) has received considerable attention in recent years. Nonetheless, it is important to consider the potential presence of as-built large pores in real world applications, e.g. due to limitations of the available LPBF system, time and cost constraints associated with producing near-perfect density and so on. In this work, recycled powder was used to fabricate AlSi10Mg specimens with sub-optimal densification by LPBF and an experimental investigation into the evolution of specimen porosity occurring under increasing tensile load was performed. A combination of high-resolution X-ray micro computed tomography (XμCT) and an in-situ micro-testing stage was employed to acquire 3D images at different loading stages. Specimens were tested in the as-built condition and following hot isostatic pressing (HIPping) or HIPping with T6. As-built porosity did not change markedly in the lead-up to brittle-like fracture. Pores within ductile HIPped specimens were uniformly elongated up to the onset of damage propagation and pore coalescence. Pore shape change occurred largely without volume change at small extension. HIPping plus T6 produced a compromise between as-built and HIPped conditions in terms of the extent of pore modification observed prior to failure.

Bibliographic note

Funding Information: The authors gratefully acknowledge the financial support of the Engineering and Physical Sciences Research Council (EPSRC) under grant reference EP/ R021694/1 , “3D in-situ based methodology for optimizing the mechanical performance of selective laser melted aluminium alloys”. Publisher Copyright: © 2021 The Authors

Details

Original languageEnglish
Article number109645
Number of pages12
JournalMaterials and Design
Volume204
Early online date9 Mar 2021
Publication statusPublished - Jun 2021

Keywords

  • in-situ X-ray micro computed tomography, Internal porosity, Laser powder bed fusion, Selective laser melting, Tensile testing