Laser diffusion nitriding of Ti-6Al-4V for improving hardness and wear resistance

Hau Chung Man, M. Bai, F. T. Cheng

Research output: Journal article publicationJournal articleAcademic researchpeer-review

63 Citations (Scopus)

Abstract

Owing to poor tribological properties, titanium (Ti) alloys are usually surface-treated to enhance their surface properties. Laser surface nitriding, among others, is a common method employed to increase hardness and wear resistance for Ti alloys. Conventional laser nitriding involves surface melting of Ti alloys in a nitrogen atmosphere. This inevitably results in a roughened surface and post-treatment might be required. The present study aims at laser diffusion nitriding Ti alloys without surface melting via carefully selecting the laser processing parameters. The nitrided surface was characterized by X-ray diffractometry (XRD), optical microscopy (OM), scanning-electron microscopy (SEM), and profilometry. The nitride layer formed was about 1.62 μm upon repeated passes. The change in surface roughness resulting from laser diffusion nitriding was only minimal. Nanoindentation measurements revealed that the hardness of the nitride layer was around 11.3 GPa, being about 2.3 times that of Ti-6Al-4V. Ball-on-slab sliding wear test recorded a reduction in wear volume by about 8 times. The results of the present work thus demonstrate the feasibility of diffusion nitriding of Ti-6Al-4V by laser treatment for enhancing its surface properties and performance.
Original languageEnglish
Pages (from-to)436-441
Number of pages6
JournalApplied Surface Science
Volume258
Issue number1
DOIs
Publication statusPublished - 15 Oct 2011

Keywords

  • Diffusion nitriding
  • Hardness
  • Laser surface treatment
  • Roughness
  • Wear

ASJC Scopus subject areas

  • Surfaces, Coatings and Films

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