The effect of ultrasonic nanocrystal surface modification on low temperature nitriding of ultra-high strength steel

Weidong Zhao, Daoxin Liu, Haifeng Qin, Xiaohua Zhang, Hao Zhang, Ruixia Zhang, Zhencheng Ren, Chi Ma, Auezhan Amanov, Young Sik Pyun, G. L. Doll, Y. Dong, C. Ye

Research output: Contribution to journalArticlepeer-review

46 Scopus citations

Abstract

In this research, a surface plastic deformation layer was induced on 300M ultra-high strength steel using ultrasonic nanocrystal surface modification (UNSM). The UNSM-treated and control specimens were then nitrided at 450 °C for 6 h. After gas nitriding, the microstructure, corrosion and wear resistance of 300M steel with and without UNSM pre-treatment were investigated. After nitriding, the UNSM-treated specimens generated a dense surface nitride layer that was thicker than that of the control specimens. The high defect density and refined lath martensite induced by UNSM were found to accelerate the nitrogen diffusion and efficiency. X-ray diffraction patterns revealed that α-Fe phase occupied the largest proportion in the nitriding layer of specimens without UNSM pre-treatment. However due to the higher nitriding efficiency, the main phase of UNSM-treated specimens after nitriding was found to be ε-Fe2-3N. Compared with the specimens without pre-treatment, UNSM-treated specimens exhibited higher surface hardness as well as higher corrosion and wear resistance after nitriding.

Original languageEnglish
Pages (from-to)205-214
Number of pages10
JournalSurface and Coatings Technology
Volume375
DOIs
StatePublished - 15 Oct 2019

Keywords

  • 300M ultra-high strength steel
  • Corrosion resistance
  • Gas nitriding
  • Surface severe plastic deformation
  • Ultrasonic nanocrystal surface modification
  • Wear resistance

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