Dislocation Density of Electron Beam Powder Bed Fusion Ti–6Al–4V Alloys Determined via Time-Of-Flight Neutron Diffraction Line-Profile Analysis

Kenta Yamanaka, Manami Mori, Yusuke Onuki, Shigeo Sato, Akihiko Chiba

Research output: Contribution to journalArticlepeer-review

Abstract

Ti–6Al–4V alloys undergo a multiple phase transformation sequence during electron beam powder bed fusion (EB-PBF) additive manufacturing, forming unique dislocation substructures. Thus, determining the dislocation density is crucial for comprehensively understanding the strengthening mechanisms and deformation behavior. This study performed time-of-flight neutron diffraction (TOF-ND) measurements of Ti–6Al–4V alloys prepared via EB-PBF and examined the dislocation density in the as-built and post-processed states using convolutional multiple whole profile (CMWP) fitting. The present TOF-ND/CMWP approach successfully determined the bulk-averaged dislocation density (6.8 × 1013 m−2) in the as-built state for the α-matrix, suggesting a non-negligible contribution of dislocation hardening. The obtained dislocation density values were comparable to those obtained by conventional and synchrotron X-ray diffraction (XRD) measurements, confirming the reliability of the analysis, and indicating that the dislocations in the α-matrix were homogeneously distributed throughout the as-built specimen. However, the negative and positive neutron scattering lengths of Ti and Al, respectively, lowered the diffraction intensity for the Ti–6Al–4V alloys, thereby decreasing the lower limit of the measurable dislocation density and making the analysis difficult.

Original languageEnglish
Article number86
JournalMetals
Volume13
Issue number1
DOIs
Publication statusPublished - 2023 Jan

Keywords

  • Ti–6Al–4V alloy
  • additive manufacturing
  • convolutional multiple whole profile (CMWP)
  • dislocation density
  • duplex microstructures
  • electron beam powder bed fusion (EB-PBF)
  • hot isostatic pressing (HIP)
  • time-of-flight neutron diffraction (TOF-ND)

Fingerprint

Dive into the research topics of 'Dislocation Density of Electron Beam Powder Bed Fusion Ti–6Al–4V Alloys Determined via Time-Of-Flight Neutron Diffraction Line-Profile Analysis'. Together they form a unique fingerprint.

Cite this