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Mechanical, structural and tribological characterisation of high nickel content alloys before and after arc activated plasma nitriding

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Mechanical, Structural and Tribological Characterisation of High Nickel Content Alloys before and after Arc Activated Plasma Nitriding …

Mechanical, Structural and Tribological Characterisation of High Nickel Content Alloys before and after Arc Activated Plasma Nitriding

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  • 1. Mechanical, Structural and Tribological Characterisation of High Nickel Content Alloys before and after Arc Activated Plasma Nitriding aintech@ain.es Mechanical, Structural and Tribological Characterisation of High Nickel Content Alloys before and after Arc Activated Plasma Nitriding
  • 2. Mechanical, Structural and Tribological Characterisation of High Nickel Content Alloys before and after Arc Activated Plasma Nitriding J. Fernández, E. Almandoz, J. Arrikaberri, S. Kulkarni, J. F. Palacio, G.G. Fuentes, J.A. García, R. Rodríguez AIN – Asociación de la Industria Navarra, Spain IVC-19 / ICN+T 2013 and partner conferences 9th – 13th September 2013, Paris (France)
  • 3. Outline 1. Introduction 2. Objectives 3. Methodology 4. Characterization: Results and discussion 5. Summary 6. Future work 7. Acknowledgments Mechanical, Structural and Tribological Characterisation of High Nickel Content Alloys before and after Arc Activated Plasma Nitriding Page 3
  • 4. Outline 1.Introduction 2. Objectives 3. Methodology 4. Characterization: Results and discussion 5. Summary 6. Future work 7. Acknowledgments Mechanical, Structural and Tribological Characterisation of High Nickel Content Alloys before and after Arc Activated Plasma Nitriding Page 4
  • 5. The alloys under study 1) Maraging Grade 300, which belongs to the group of maraging steels with 18% Ni and Co containing. C (%) Ni (%) Co (%) Mo (%) Ti (%) Al (%) Fe (%) Specified < 0.03 17-19 8.5-9.5 4.7-5.2 0.6-0.7 < 0.15 Balance Measured 0.008 17.31 9.05 5.10 0.66 0.11 Balance Chemical composition of Maraging Grade 300 Samples 30.3 ± 0.2 HRc after quenching at 820 ºC during 1 h 52.1 ± 0.2 HRc after aging at 485 ºC during 3h Dimensions: Ø = 35 mm; thickness = 5 mm Grinded and polished to Ra ~ 10 nm Mechanical, Structural and Tribological Characterisation of High Nickel Content Alloys before and after Arc Activated Plasma Nitriding Page 5
  • 6. The alloys under study 2) INCONEL alloy 600, which belongs to the group of nickel superalloys. C (%) Cr (%) Fe (%) Mn (%) Si (%) Cu (%) S (%) Ni (%) Specified < 0.15 14-17 6-10 ≤1 ≤ 0.50 ≤ 0.50 ≤ 0.015 Balance Measured 0.12 16.3 9.1 0.54 0.43 0.32 0.011 Balance Chemical composition of INCONEL alloy 600 Samples 17.0 ± 0.2 HRc Dimensions: Ø = 40 mm; thickness = 5 mm Grinded and polished to Ra ~ 10 nm Mechanical, Structural and Tribological Characterisation of High Nickel Content Alloys before and after Arc Activated Plasma Nitriding Page 6
  • 7. The alloys under study 3) INCONEL alloy 718, which belongs to the group of nickel superalloys. C (%) Cr (%) Fe (%) Mo (%) Ti (%) Al (%) Si (%) B (%) Specified ≤ 0.0080 17-21 17 2.8-3.3 0.65-1.15 0.20-0.80 ≤ 0.35 ≤0.0060 Measured 0.006 17.6 17.1 2.9 0.96 0.55 0.30 0.002 Co (%) Cu (%) Mn (%) Nb (%) P (%) S (%) Ni (%) Specified ≤ 1.0 ≤ 0.30 ≤ 0.35 4.75-5.5 ≤ 0.015 ≤ 0.015 Balance Measured 0.75 0.22 0.26 5.1 0.009 0.012 Balance Chemical composition of INCONEL alloy 718 Samples 41.8 ± 0.8 HRc Dimensions: Ø = 40 mm; thickness = 4 mm Grinded and polished to Ra ~ 10 nm Mechanical, Structural and Tribological Characterisation of High Nickel Content Alloys before and after Arc Activated Plasma Nitriding Page 7
  • 8. Outline 1. Introduction 2.Objectives 3. Methodology 4. Characterization: Results and discussion 5. Summary 6. Future work 7. Acknowledgments Mechanical, Structural and Tribological Characterisation of High Nickel Content Alloys before and after Arc Activated Plasma Nitriding Page 8
  • 9. Objectives Study the mechanical, structural and tribological properties of high nickel content alloys before and after an arc activated plasma nitriding process. What for? Increasing the superficial hardness Increasing the wear resistance (room & high temperature) Mechanical, Structural and Tribological Characterisation of High Nickel Content Alloys before and after Arc Activated Plasma Nitriding Page 9
  • 10. Outline 1. Introduction 2. Objectives 3.Methodology 4. Characterization: Results and discussion 5. Summary 6. Future work 7. Acknowledgments Mechanical, Structural and Tribological Characterisation of High Nickel Content Alloys before and after Arc Activated Plasma Nitriding Page 10
  • 11. Arc activated plasma nitriding Spanish patent: ES 2 344 981 B1 in 2011 and European patent EP 2 369 028 B1 in 2013. 1: Reactor 2: Samples 3: Electric arc discharge units 4: Heat source 5: Sample holder 6: Electron collector (anode) - 6.1: Electric field concentrator spirals 7: Gas inlet 8: Vacuum system 9: Pulsed DC current source 10: DC current source 11: DC power system Mechanical, Structural and Tribological Characterisation of High Nickel Content Alloys before and after Arc Activated Plasma Nitriding Page 11
  • 12. Arc activated plasma nitriding Steps eIonized gas - N + Ar (+H ) e 2 2 + + e- + Vacuum: 5x10-3 Pa Pre-heating: 350 ºC Cleaning: Ar Nitriding: 1 Pa, 425 ºC, 60 min 90 sccm N2 & Ar Cooling down PVD scheme Mechanical, Structural and Tribological Characterisation of High Nickel Content Alloys before and after Arc Activated Plasma Nitriding Page 12
  • 13. Arc activated plasma nitriding Characteristics High ionization rate Low pressure Benefits High ratio of active specimens Versatility for future treatments (DUPLEX treatments: nitriding + PVD, nitriding + oxidation) No formation of white layer Labelling Material Nitrided Maraging 300 MAR-3 MAR-3N INCONEL 600 METAPLAS PVD MZR 323 equipment Untreated INC-6 INC-6N INCONEL 718 INC-7 INC-7N Mechanical, Structural and Tribological Characterisation of High Nickel Content Alloys before and after Arc Activated Plasma Nitriding Page 13
  • 14. Outline 1. Introduction 2. Objectives 3. Methodology 4. Characterization: Results and discussion 5. Summary 6. Future work 7. Acknowledgments Mechanical, Structural and Tribological Characterisation of High Nickel Content Alloys before and after Arc Activated Plasma Nitriding Page 14
  • 15. Chemical analysis: GD-OES 70 MAR-3N C Fe Mo N O Ti Co Ni 60 Atomic % 50 40 30 20 10 INC-6N INC-7N 0 3 70 C Cr Fe N O Si Ni Cu Mn 60 50 Atomic % 6 40 30 20 9 12 Depth (microns) 15 70 18 Al C Cr Fe Mo N O Ti Co Ni 60 50 Atomic % 0 40 30 20 10 10 0 0 0 1 2 3 Depth (microns) 4 5 0 1 2 3 4 5 Depth (microns) Mechanical, Structural and Tribological Characterisation of High Nickel Content Alloys before and after Arc Activated Plasma Nitriding Page 15
  • 16. Chemical analysis: GD-OES Nitrogen profiles MAR-3N 12 18 INC-6N INC-7N 16 14 N (atomic %) N (atomic %) 10 8 6 4 12 10 8 6 4 2 2 0 0 2 4 6 8 10 12 Depth(microns) 14 16 18 20 0 0,0 0,5 1,0 1,5 2,0 2,5 Depth (microns) • MAR-3N shows longer profiles with less nitrogen concentration than INCONEL alloys, and a longer diffusion zone. • Both INCONEL alloys show very similar nitrogen profile, with a plateau of ~ 14-15% of nitrogen content, that decreases drastically . Mechanical, Structural and Tribological Characterisation of High Nickel Content Alloys before and after Arc Activated Plasma Nitriding Page 16 3,0
  • 17. Microscopy: SEM of the fracture MAR-3 INC-6 INC-7 MAR-3N INC-6N INC-7N Mechanical, Structural and Tribological Characterisation of High Nickel Content Alloys before and after Arc Activated Plasma Nitriding Page 17
  • 18. Mechanical properties (Nanoindentation) Test parameters • 10 x10 indents, 25 µm space between indents • Decreasing Loads from 10 mN to 100 µN (in 100µN steps) • Loading rate constant • Berkovich Tip radius (150 nm) • E and H Oliver and Pharr Method HYSITRON nanoindenter TI950 Mechanical, Structural and Tribological Characterisation of High Nickel Content Alloys before and after Arc Activated Plasma Nitriding Page 18
  • 19. Mechanical properties (Nanoindentation) REFERENCES (Non nitrided samples): MAR-3, INC-6 & INC-7 Er values between 150 GPa and 200 GPa for all the samples. MAR-3 INC-6 INC-7 H values of ~ 10 GPa for MAR-3 and INC-7 and of ~ 7 GPa for INC-6. Sample MAR-3 52.1 ± 0.2 INC-6 17.0 ± 0.2 INC-7 MAR-3 INC-6 INC-7 HRc 41.8 ± 0.8 Mechanical, Structural and Tribological Characterisation of High Nickel Content Alloys before and after Arc Activated Plasma Nitriding Page 19
  • 20. Mechanical properties (Nanoindentation) MAR-3 & MAR-3N MAR-3N MAR-3 Slightly lower Er compared to the as received MAR-3. Increase of hardness by 40%, especially at higher loads. MAR-3N MAR-3 Mechanical, Structural and Tribological Characterisation of High Nickel Content Alloys before and after Arc Activated Plasma Nitriding Page 20
  • 21. Mechanical properties (Nanoindentation) INC-6 & INC-6N Similar Red. Modulus. INC-6N INC-6 Dramatic increase of superficial hardness (more than x2) with respect to the as received INC-6. INC-6N INC-6 Mechanical, Structural and Tribological Characterisation of High Nickel Content Alloys before and after Arc Activated Plasma Nitriding Page 21
  • 22. Mechanical properties (Nanoindentation) INC-7 & INC-7N Similar Red. Modulus INC-7N INC-7 Dramatic increase of hardness (x2) with respect to the as received INC-7, especially at higher loads. INC-7N INC-7 Mechanical, Structural and Tribological Characterisation of High Nickel Content Alloys before and after Arc Activated Plasma Nitriding Page 22
  • 23. XRD analysis MAR-3 & MAR-3N Cr Kα (λ = 2.29110 Å) BB, 40 KV, 30 mA Room T, 0.02º step, 0.5 s/step There is no austenitic phase 43.64º, 50.76º & 74.58º for γ(111), γ(200) & γ(220). Fe3N Fe4N Fe-α (101) a.u. Peaks of Fe4N, FeNi3N, Fe3N and Fe3NiN are observed.* MAR-3 MAR-3N 40 50 60 70 Fe3N XRD test conditions Fe-α (200) 80 90 100 110 120 2 Theta *K. Shetty, S. Kumar, P. Raghothama Rao, Surface & Coatings Technol., 203 (2009) 1530-1536 Mechanical, Structural and Tribological Characterisation of High Nickel Content Alloys before and after Arc Activated Plasma Nitriding Page 23
  • 24. XRD analysis INC-7 & INC-7N γ (111) u.a. 50 55 60 65 70 75 80 85 90 50 55 60 2 Theta γ (2 0 0) INC-7 INC-7N γΝ (2 0 0) CrN γ (2 0 0) γΝ (1 1 1) INC-6 INC-6N γΝ (2 0 0) Fe4N γ (111) a.u. γΝ (1 1 1) INC-6 & INC-6N 65 70 75 80 85 90 2 Theta γ phase is observed in the as received samples, whereas in the nitrided samples a mixture of γ and γN phases is present*. Fe4N is also formed in INC-6N and CrN is observed in INC-7N. *S. Chollet et al., Surface & Coatings Technol., (2013) In press. Mechanical, Structural and Tribological Characterisation of High Nickel Content Alloys before and after Arc Activated Plasma Nitriding Page 24
  • 25. Wear (Room T) K wear at room temperature Pin-on-disc configuration Counter ball: alumina; Ø = 6 mm 20000 cycles, 2N, 10 cm/s R = 7, 9 and 11 mm 18 -14 3 m /Nm 15 Kwear x10 Wear test conditions 12 Sample MAR-3 MAR-3 MAR-3N INC-6 INC-6N INC-7 INC-7N 0.099 ± 0.008 INC-7 0,1 0,0 14 ± 4 INC-6N 3 2.6 ± 0.2 INC-6 6 3.8 ± 0.5 MAR-3N 9 Kwear x10-14 m3/Nm 17 ± 2 INC-7N 0.094 ± 0.010 Sample Nitrided maraging does not show an improvement on wear resistance whereas both nitrided INCONEL alloys show an improvement of 2 orders of magnitude compared to their respective non-treated samples. Mechanical, Structural and Tribological Characterisation of High Nickel Content Alloys before and after Arc Activated Plasma Nitriding Page 25
  • 26. Wear and COF (RT) MAR-3 MAR-3N Wear test conditions Pin-on-disc configuration Counter ball: alumina; Ø = 6 mm 20000 cycles, 2N, 10 cm/s R = 7, 9 and 11 mm INC-6 INC-6N Sample MAR-3 0.85 ± 0.05 INC-6 0.84 ± 0.06 INC-6N 0.86 ± 0.06 INC-7 0.67 ± 0.07 INC-7N INC-7N 0.92 ± 0.07 MAR-3N INC-7 COF 0.66 ± 0.04 Mechanical, Structural and Tribological Characterisation of High Nickel Content Alloys before and after Arc Activated Plasma Nitriding Page 26
  • 27. Wear and COF (RT) MAR-3 INC-6 500 µm 500 µm MAR-3N INC-7 INC-7N INC-6N 500 µm 500 µm 500 µm Mechanical, Structural and Tribological Characterisation of High Nickel Content Alloys before and after Arc Activated Plasma Nitriding 500 µm Page 27
  • 28. Wear (at 450 ºC) 16 Wear test conditions Pin-on-disc configuration Counter ball: alumina; Ø = 6 mm 20000 cycles, 2N, 10 cm/s 10 8 Kwear x10 3 12 -14 m /Nm 14 6 4 2 0 MAR-3N INC-6 INC-6N INC-7 INC-7N MAR-3 10.5 ± 1.0 MAR-3N 13.2 ± 1.0 8.2 ± 3.8 3.1 ± 0.3 INC-7 8.1 ± 2.0 INC-7N MAR-3 Kwear x10-14 m3/Nm INC-6N Sample Sample INC-6 MAR-3 MAR-3N INC-6 INC-6N INC-7 INC-7N 2.7 ± 0.5 Mechanical, Structural and Tribological Characterisation of High Nickel Content Alloys before and after Arc Activated Plasma Nitriding Page 28
  • 29. Wear (at 450 ºC) MAR-3 MAR-3N Wear test conditions Pin-on-disc configuration Counter ball: alumina; Ø = 6 mm 20000 cycles, 2N, 10 cm/s INC-6 INC-6N MAR-3N shows no improvement compared to the non treated MAR-3 INC-7 INC-7N Nitrided INCONEL alloys show a slight improvement. Mechanical, Structural and Tribological Characterisation of High Nickel Content Alloys before and after Arc Activated Plasma Nitriding Page 29
  • 30. On going work 18 INC-7 14 N (atomic %) When comparing with other processes (longer time, higher temperature): 500 ºC, 1,5 h 480 ºC, 1,5 h INC-7N 16 12 10 8 6 4 2 0 • 480 ºC – 1.5h • 500 ºC – 1.5h 0 1 2 3 4 5 6 7 8 Depth (microns) Nanoindentation results are similar at high loads, despite the thicker nitrided layers of the above mentioned processes. Mechanical, Structural and Tribological Characterisation of High Nickel Content Alloys before and after Arc Activated Plasma Nitriding 500 ºC, 1,5h 480 ºC, 1,5h INC-7N INC-7 Page 30
  • 31. On going work MAR-3 MAR-3N 500 ºC -1.5h 480 ºC -1.5h Sample Kwear x10-14 m3/Nm at RT MAR-3 3.8 ± 0.5 MAR-3N 2.6 ± 0.2 480 ºC-1.5h 1.4 ± 0.5 500 ºC-1.5h Kwear x10-14 m3/Nm at 450 ºC MAR-3 10.5 ± 1.0 MAR-3N 13.2 ± 1.0 480 ºC-1.5h 8.1 ± 0.8 500 ºC-1.5h 7.9 ± 0.5 15 10 5 2.1 ± 0.3 Sample N (atomic %) 20 0 0 10 20 30 40 50 60 70 80 Depth (microns) When comparing with other processes (longer time, higher temperature): • 480 ºC – 1.5h • 500 ºC – 1.5h Longer profiles with higher nitrogen concentration in the surface are obtained. Tribological tests show a slight improvement on wear resistance. Mechanical, Structural and Tribological Characterisation of High Nickel Content Alloys before and after Arc Activated Plasma Nitriding Page 31
  • 32. Outline 1. Introduction 2. Objectives 3. Methodology 4. Characterization: Results and discussion 5.Summary 6. Future work 7. Acknowledgments Mechanical, Structural and Tribological Characterisation of High Nickel Content Alloys before and after Arc Activated Plasma Nitriding Page 32
  • 33. Summary Arc activated plasma nitriding processes have been carried out for the nitriding of a series of high nickel content alloys (Maraging 300, INCONEL 600 and INCONEL 718). Chemical, mechanical, microstructural and tribological analysis of the non treated and nitrided samples has been done. Maraging steel 300 has shown long nitriding profiles. The formation of Fe nitrides explains the superficial hardness increase. INCONEL alloys 600 and 718 have shown short nitrogen profiles but with nitrogen concentrations up to 14-15%. The formation of γN phase and Fe4N (INC-6N) and CrN (INC-7N) compounds permits to improve wear resistance of both alloys 2 order of magnitude at room temperature. Longer and higher nitrogen profiles are possible to obtain when varying different process parameters (temperature, time,…) Mechanical, Structural and Tribological Characterisation of High Nickel Content Alloys before and after Arc Activated Plasma Nitriding Page 33
  • 34. Outline 1. Introduction 2. Objectives 3. Methodology 4. Characterization: Results and discussion 5. Summary 6.Future work 7. Acknowledgments Mechanical, Structural and Tribological Characterisation of High Nickel Content Alloys before and after Arc Activated Plasma Nitriding Page 34
  • 35. Future work Characterization of corrosion properties of nitrided samples EBSD characterization of nitrided samples Optimization of the nitriding process for each alloy Mechanical, Structural and Tribological Characterisation of High Nickel Content Alloys before and after Arc Activated Plasma Nitriding
  • 36. Outline 1. Introduction 2. Objectives 3. Methodology 4. Characterization: Results and discussion 5. Summary 6. Future work 7.Acknowledgments Mechanical, Structural and Tribological Characterisation of High Nickel Content Alloys before and after Arc Activated Plasma Nitriding Page 36
  • 37. Acknowledgments The authors would like to thank to the Departamento de Innovación y Empleo of Gobierno de Navarra for their support in Super-Maraging project. Thank you for your kind attention! Mechanical, Structural and Tribological Characterisation of High Nickel Content Alloys before and after Arc Activated Plasma Nitriding Page 37