Surface nanocrystallization by ultrasonic nano-crystal surface modification and its effect on gas nitriding of Ti6Al4V alloy

Jun Liu, Sergey Suslov, Azhar Vellore, Zhencheng Ren, Auezhan Amanov, Young Sik Pyun, Ashlie Martini, Yalin Dong, Chang Ye

Research output: Contribution to journalArticle

7 Citations (Scopus)


The effects of Ultrasonic Nanocrystal Surface Modification (UNSM) on the gas nitriding behavior of Ti6Al4V alloy have been investigated. Gas nitriding was performed at 700 and 800 °C. The microstructure after UNSM and gas nitriding was characterized using X-ray diffraction, scanning electron microscopy and transmission electron microscopy. Microstructural investigations revealed the formation of an approximately 10 µm thick severe plastic deformation layer as well as nano-grains after UNSM treatment. The UNSM-treated Ti6Al4V alloy formed 0.26 µm and 1.35 µm thick nitride layers after nitriding at 700 °C and 800 °C, respectively, and UNSM resulted in an increased layer thickness relative to untreated samples at both temperatures. The results suggest that nitrogen adsorption and reaction capability were enhanced in the UNSM-treated Ti6Al4V alloy. This enhancement can be attributed to high-density dislocations and grain boundaries that were introduced by UNSM and served as efficient channels for nitrogen diffusion.

Original languageEnglish
Pages (from-to)335-343
Number of pages9
JournalMaterials Science and Engineering A
Publication statusPublished - 24 Oct 2018



  • Gas nitriding
  • Nanocrystalline
  • Scratch test
  • Surface severe plastic deformation
  • Ti64
  • Ultrasonic nanocrystal surface modification

ASJC Scopus subject areas

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

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