Enhancement of CP-titanum wear resistance using a two-step CO2 laser-sustained plasma nitriding process

Amar M. Kamat, Albert Eliot Segall, Stephen M. Copley, Judith Todd Copley

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

In this paper, a method of forming hard, wide-area, crack-free, and wear-resistant nitrided cases on commercially-pure titanium using a 3.5 kW CO2 laser-sustained plasma is described. This surface hardening method was comprised of two steps: (1) a laser-sustained nitrogen plasma was first used to nitride the titanium substrate; and (2) a laser-sustained argon plasma was then employed to remelt the nitrided layer deposited in the first step. Previous research using single laser trail experiments had shown that the (second) remelting step can eliminate cracks formed during the (first) nitriding step and homogenize the nitrided layer. In this work, the two-step nitriding-remelting process was extended to wider surface areas by depositing multiple overlapping trails at four different nitriding speeds and a constant remelting speed. The hardened layer was characterized using x-ray diffraction (XRD), optical metallography, and hardness testing. Reciprocating ball-on-flat wear tests were conducted to assess the wear resistance of the nitrided case, with the wear scar being characterized using scanning electron microscopy (SEM) and optical profilometry. Crack-free, hard cases of depths up to 600 μm and average hardness values up to 641 ± 86 HV0.3 were observed. The LSP nitriding-remelting treatment was found to improve the wear resistance of the base metal (CP-Ti) by up to 80%.

Original languageEnglish (US)
Pages (from-to)229-238
Number of pages10
JournalSurface and Coatings Technology
Volume325
DOIs
StatePublished - Sep 25 2017

Fingerprint

Remelting
nitriding
Nitriding
wear resistance
Wear resistance
Plasmas
melting
Lasers
augmentation
Wear of materials
Cracks
cracks
lasers
Titanium
Argon lasers
Hardness testing
Nitrogen plasma
hardness
titanium
Profilometry

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Materials Chemistry

Cite this

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title = "Enhancement of CP-titanum wear resistance using a two-step CO2 laser-sustained plasma nitriding process",
abstract = "In this paper, a method of forming hard, wide-area, crack-free, and wear-resistant nitrided cases on commercially-pure titanium using a 3.5 kW CO2 laser-sustained plasma is described. This surface hardening method was comprised of two steps: (1) a laser-sustained nitrogen plasma was first used to nitride the titanium substrate; and (2) a laser-sustained argon plasma was then employed to remelt the nitrided layer deposited in the first step. Previous research using single laser trail experiments had shown that the (second) remelting step can eliminate cracks formed during the (first) nitriding step and homogenize the nitrided layer. In this work, the two-step nitriding-remelting process was extended to wider surface areas by depositing multiple overlapping trails at four different nitriding speeds and a constant remelting speed. The hardened layer was characterized using x-ray diffraction (XRD), optical metallography, and hardness testing. Reciprocating ball-on-flat wear tests were conducted to assess the wear resistance of the nitrided case, with the wear scar being characterized using scanning electron microscopy (SEM) and optical profilometry. Crack-free, hard cases of depths up to 600 μm and average hardness values up to 641 ± 86 HV0.3 were observed. The LSP nitriding-remelting treatment was found to improve the wear resistance of the base metal (CP-Ti) by up to 80{\%}.",
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Enhancement of CP-titanum wear resistance using a two-step CO2 laser-sustained plasma nitriding process. / Kamat, Amar M.; Segall, Albert Eliot; Copley, Stephen M.; Todd Copley, Judith.

In: Surface and Coatings Technology, Vol. 325, 25.09.2017, p. 229-238.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Enhancement of CP-titanum wear resistance using a two-step CO2 laser-sustained plasma nitriding process

AU - Kamat, Amar M.

AU - Segall, Albert Eliot

AU - Copley, Stephen M.

AU - Todd Copley, Judith

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N2 - In this paper, a method of forming hard, wide-area, crack-free, and wear-resistant nitrided cases on commercially-pure titanium using a 3.5 kW CO2 laser-sustained plasma is described. This surface hardening method was comprised of two steps: (1) a laser-sustained nitrogen plasma was first used to nitride the titanium substrate; and (2) a laser-sustained argon plasma was then employed to remelt the nitrided layer deposited in the first step. Previous research using single laser trail experiments had shown that the (second) remelting step can eliminate cracks formed during the (first) nitriding step and homogenize the nitrided layer. In this work, the two-step nitriding-remelting process was extended to wider surface areas by depositing multiple overlapping trails at four different nitriding speeds and a constant remelting speed. The hardened layer was characterized using x-ray diffraction (XRD), optical metallography, and hardness testing. Reciprocating ball-on-flat wear tests were conducted to assess the wear resistance of the nitrided case, with the wear scar being characterized using scanning electron microscopy (SEM) and optical profilometry. Crack-free, hard cases of depths up to 600 μm and average hardness values up to 641 ± 86 HV0.3 were observed. The LSP nitriding-remelting treatment was found to improve the wear resistance of the base metal (CP-Ti) by up to 80%.

AB - In this paper, a method of forming hard, wide-area, crack-free, and wear-resistant nitrided cases on commercially-pure titanium using a 3.5 kW CO2 laser-sustained plasma is described. This surface hardening method was comprised of two steps: (1) a laser-sustained nitrogen plasma was first used to nitride the titanium substrate; and (2) a laser-sustained argon plasma was then employed to remelt the nitrided layer deposited in the first step. Previous research using single laser trail experiments had shown that the (second) remelting step can eliminate cracks formed during the (first) nitriding step and homogenize the nitrided layer. In this work, the two-step nitriding-remelting process was extended to wider surface areas by depositing multiple overlapping trails at four different nitriding speeds and a constant remelting speed. The hardened layer was characterized using x-ray diffraction (XRD), optical metallography, and hardness testing. Reciprocating ball-on-flat wear tests were conducted to assess the wear resistance of the nitrided case, with the wear scar being characterized using scanning electron microscopy (SEM) and optical profilometry. Crack-free, hard cases of depths up to 600 μm and average hardness values up to 641 ± 86 HV0.3 were observed. The LSP nitriding-remelting treatment was found to improve the wear resistance of the base metal (CP-Ti) by up to 80%.

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