Microstructure and tensile properties of selectively laser-melted and of HIPed laser-melted Ti-6Al-4V

Chunlei Qiu, Nicholas J E Adkins, Moataz M. Attallah

Research output: Contribution to journalArticlepeer-review

373 Citations (Scopus)

Abstract

Ti-6Al-4V samples have been prepared by selective laser melting (SLM) with varied processing conditions. Some of the samples were stress-relieved or hot isostatically pressed (HIPed). The microstructures of all samples were characterised using optical microscopy (OM), scanning electron microscopy (SEM) and X-ray diffraction (XRD) and the tensile properties measured before and after HIPing. It was found that the porosity level generally decreased with increase of laser power and laser scanning speed. Horizontally built samples were found to have a higher level of porosity than vertically built samples. The as-fabricated microstructure was dominated by columnar grains and martensites. HIPing closed the majority of the pores and also fully transformed the martensite into α and β phases. The as-fabricated microstructure exhibits very high tensile strengths but poor ductility with elongation generally smaller than 10%. The horizontally built samples show even lower elongation than vertically built samples. HIPing considerably improved ductility but led to a reduction in strength. With HIPing, the SLMed samples were found to show tensile properties comparable with those thermomechanically processed and annealed samples.

Original languageEnglish
Pages (from-to)230-239
Number of pages10
JournalMaterials Science and Engineering A
Volume578
DOIs
Publication statusPublished - 20 Aug 2013

Keywords

  • Hot isostatic pressing
  • Microstructure
  • Selective laser melting
  • Tensile behaviour
  • Titanium alloys

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering
  • Mechanics of Materials

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