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Michiharu Ogawa - One of the best experts on this subject based on the ideXlab platform.
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Surface hardening of biomedical Ti–29Nb–13Ta–4.6Zr and Ti–6Al–4V ELI by Gas Nitriding
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2008Co-Authors: Masaaki Nakai, Mitsuo Niinomi, Toshikazu Akahori, Naofumi Ohtsu, Hideki Nishimura, Hiroyuki Toda, Hisao Fukui, Michiharu OgawaAbstract:Abstract The microstructure and hardness near the surface of a biomedical titanium alloy, Ti–29Nb–13Ta–4.6Zr (TNTZ), subjected to Gas Nitriding at 1023–1223 K was investigated in comparison with the conventional biomedical Ti–6Al–4V ELI (Ti64). After Gas Nitriding, the microstructure near the specimen surface was observed by optical microscopy, X-ray diffraction (XRD), Auger electron spectroscopy (AES), and X-ray photoelectron spectroscopy (XPS). In both alloys, two types of titanium nitrides (TiN and Ti 2 N) are formed and the α phase is precipitated by Gas Nitriding. Furthermore, the oxygen impurity in the Gas Nitriding atmosphere reacts with the titanium nitrides; thus, TiO 2 is formed at the outermost titanium nitride layer. The surface hardening was also evaluated by Vickers hardness measurement. The Vickers hardness near the surface of TNTZ and Ti64 increases significantly by Gas Nitriding.
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surface hardening of biomedical ti 29nb 13ta 4 6zr and ti 6al 4v eli by Gas Nitriding
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2008Co-Authors: Masaaki Nakai, Mitsuo Niinomi, Toshikazu Akahori, Naofumi Ohtsu, Hideki Nishimura, Hiroyuki Toda, Hisao Fukui, Michiharu OgawaAbstract:Abstract The microstructure and hardness near the surface of a biomedical titanium alloy, Ti–29Nb–13Ta–4.6Zr (TNTZ), subjected to Gas Nitriding at 1023–1223 K was investigated in comparison with the conventional biomedical Ti–6Al–4V ELI (Ti64). After Gas Nitriding, the microstructure near the specimen surface was observed by optical microscopy, X-ray diffraction (XRD), Auger electron spectroscopy (AES), and X-ray photoelectron spectroscopy (XPS). In both alloys, two types of titanium nitrides (TiN and Ti 2 N) are formed and the α phase is precipitated by Gas Nitriding. Furthermore, the oxygen impurity in the Gas Nitriding atmosphere reacts with the titanium nitrides; thus, TiO 2 is formed at the outermost titanium nitride layer. The surface hardening was also evaluated by Vickers hardness measurement. The Vickers hardness near the surface of TNTZ and Ti64 increases significantly by Gas Nitriding.
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Hard-Ceramic Layer Formed on Ti-29Nb-13Ta-4.6Zr and Ti-6Al-4V ELI during Gas Nitriding
Materials Science Forum, 2007Co-Authors: Masaaki Nakai, Mitsuo Niinomi, Toshikazu Akahori, Naofumi Ohtsu, Hideki Nishimura, Hiroyuki Toda, Hisao Fukui, Michiharu OgawaAbstract:The surface of Ti-29Nb-13Ta-4.6Zr (TNTZ) subjected to Gas Nitriding at 1023–1223 K was investigated in comparison with the conventional biomedical titanium alloy, Ti-6Al-4V ELI (Ti64). After Gas Nitriding, the microstructures near the surface of these alloys were observed by optical microscopy, X-ray diffraction, Auger electron spectroscopy, and X-ray photoelectron spectroscopy. In both alloys, two titanium nitrides (TiN and Ti2N) are formed and the α phase precipitated by Gas Nitriding. Furthermore, oxygen impurity in the Gas Nitriding atmosphere reacts with the titanium nitrides; thus, TiO2 is formed at the outermost titanium nitride layer. The surface hardening was also evaluated by Vickers hardness measurement. The Vickers hardness near the surface of TNTZ and Ti64 increases significantly by Gas Nitriding.
S. Malinov - One of the best experts on this subject based on the ideXlab platform.
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Surface Gas Nitriding: mechanical properties, morphology, corrosion
Titanium Alloys, 2020Co-Authors: S. MalinovAbstract:Microindentation hardness testing using both Vickers and Knoop indenters is used to analyse the hardness evolution of nitrided titanium alloys in relation to the Nitriding processing parameters and alloy composition. The microhardness increases with increase of the temperature and time of Nitriding. This is followed by discussions on tensile properties and fatigue performance after Nitriding, and the surface morphology of the alloys in relation to the initial surface roughness and Nitriding processing parameters. The corrosion behaviour of the titanium alloys before and after Gas Nitriding in response to the corrosive conditions and alloy composition is examined in the final part of the chapter.
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Surface Gas Nitriding: phase composition and microstructure
Titanium Alloys, 2020Co-Authors: S. MalinovAbstract:This chapter is about experimental research using differential scanning calorimeter while Nitriding titanium alloys at various temperatures and for various periods. X-ray diffraction technique reveals the phase transformations that occur during Gas Nitriding. Because of the nitrogen interaction, a nitrided layer is formed that consists of titanium nitrides, followed by an interstitial solution of nitrogen in titanium. The microstructural changes in relation to the alloy composition and processing parameters are detailed. The microstructure of alloys nitrided at temperatures below their β-transus temperatures is uniform and homogeneous. With an increase of temperature above their β-transus temperatures, the microstructure changes to irregular.
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Studying and modeling surface Gas Nitriding for titanium alloys
JOM, 2007Co-Authors: A. Zhecheva, S. MalinovAbstract:In this article, experimental studies for the Nitriding of four titanium alloys at different temperatures and for different periods of time are summarized. The studies focused on microstructural changes in relation to the alloy composition and processing parameters; microindentation hardness testing on the nitrided titanium alloys to analyze their hardness evolution; and the corrosion behavior of titanium alloys before and after Gas Nitriding in response to the corrosive condition. In addition, models were developed to simulate and monitor the evolution of surface layers during the Gas Nitriding of titanium alloys.
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titanium alloys after surface Gas Nitriding
Surface & Coatings Technology, 2006Co-Authors: A. Zhecheva, S. MalinovAbstract:Abstract Experimental studies using differential scanning calorimetry (DSC) for Nitriding of four titanium-alloys near α Ti–8Al–1Mo–1V, near α Ti–6Al–2Sn–4Zr–2Mo, α + β Ti–6Al–4V and near β Ti–10V–2Fe–3Al at different temperatures and for different periods of time are presented. The X-ray diffraction (XRD) technique was used in order to study the phase transformations that occur during Gas Nitriding. As a result of the nitrogen interaction, a nitrided layer was formed that consists of titanium nitrides, followed by an interstitial solution of nitrogen in the hcp α titanium phase. The microstructural changes of these alloys in relation to the alloy composition and processing parameters were studied. It was found that the microstructure of alloys nitrided at temperatures below their β transus temperatures for various periods of time is uniform and homogeneous. With the increase of the temperature above their β transus temperatures the microstructure changes to irregular. Microindentation hardness testing using a Knoop indenter was conducted on the nitrided titanium alloys to analyse their hardness evolution in relation to the Nitriding processing parameters and alloy composition. It was found that the microhardness increases with the increase of the temperature and time of Nitriding. The surface morphology of the Ti–6Al–2Sn–4Zr–2Mo alloy in relation to the Nitriding processing parameters was analysed.
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surface Gas Nitriding of ti 6al 4v and ti 6al 2sn 4zr 2mo 0 08si alloys
Zeitschrift Fur Metallkunde, 2003Co-Authors: A. Zhecheva, S. MalinovAbstract:Abstract The paper presents results from thermochemical surface Gas Nitriding of Ti-6Al-4V and Ti-6Al-2Sn-4Zr-2Mo-0.08Si alloys using differential scanning calorimetry equipment. The experiments were carried out in nitrogen atmosphere at temperatures of 950 and 1050°C for 1, 3 and 5 h. Results for the surface hardness, the microhardness profiles and the thickness of the nitrided layers were obtained. Microstructure analyses were made by optical microscopy. X-ray diffraction analyses indicated new phases formed (TiN, TiN0.3, Ti2N and TiO2), depending on the time and the temperature of Nitriding. The obtained thickness of the nitrided layers was in the range 60–320 μm depending on the process parameters. The Vickers microhardness along the cross-section depth varied between 610 and 1700.
Chang Ye - One of the best experts on this subject based on the ideXlab platform.
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surface nanocrystallization by ultrasonic nano crystal surface modification and its effect on Gas Nitriding of ti6al4v alloy
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2018Co-Authors: Sergey Suslov, Yalin Dong, Azhar Vellore, Auezhan Amanov, Young Sik Pyun, Ashlie Martini, Chang YeAbstract:Abstract 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.
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Ultrasonic Nano-Crystal Surface Modification Assisted Gas Nitriding of Ti6Al4V Alloy
Volume 2: Additive Manufacturing; Materials, 2017Co-Authors: Chi Ma, Yalin Dong, Chang YeAbstract:The effects of Ultrasonic Nanocrystal Surface Modification (UNSM) on the Gas Nitriding of Ti6Al4V alloy has been investigated. The Gas Nitriding was performed at 700 and 800 °C. The microstructure after UNSM and Gas Nitriding was characterized using X-ray diffraction and scanning electron microscopy. Microstructural investigations revealed the formation of an approximately 10 μm thick severe plastic deformation (SPD) layer after UNSM treatment. After Nitriding at 700 °C and 800 °C, a compound layer consisting of an approximately 0.2 μm and 1.9 μm thick nitride layer was observed in UNSM-treated Ti6Al4V alloy, which exhibits a nearly two-fold increase in nitride layer thickness as compared with the un-treated sample. This suggests that the nitrogen adsorption and the reaction capability are enhanced in the UNSM-treated Ti6Al4V alloy. This enhancement can be attributed to the high density dislocations and grain boundaries introduced by UNSM that serve as efficient diffusivity channels for interstitial Gaseous atoms.
Masaaki Nakai - One of the best experts on this subject based on the ideXlab platform.
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Surface hardening of biomedical Ti–29Nb–13Ta–4.6Zr and Ti–6Al–4V ELI by Gas Nitriding
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2008Co-Authors: Masaaki Nakai, Mitsuo Niinomi, Toshikazu Akahori, Naofumi Ohtsu, Hideki Nishimura, Hiroyuki Toda, Hisao Fukui, Michiharu OgawaAbstract:Abstract The microstructure and hardness near the surface of a biomedical titanium alloy, Ti–29Nb–13Ta–4.6Zr (TNTZ), subjected to Gas Nitriding at 1023–1223 K was investigated in comparison with the conventional biomedical Ti–6Al–4V ELI (Ti64). After Gas Nitriding, the microstructure near the specimen surface was observed by optical microscopy, X-ray diffraction (XRD), Auger electron spectroscopy (AES), and X-ray photoelectron spectroscopy (XPS). In both alloys, two types of titanium nitrides (TiN and Ti 2 N) are formed and the α phase is precipitated by Gas Nitriding. Furthermore, the oxygen impurity in the Gas Nitriding atmosphere reacts with the titanium nitrides; thus, TiO 2 is formed at the outermost titanium nitride layer. The surface hardening was also evaluated by Vickers hardness measurement. The Vickers hardness near the surface of TNTZ and Ti64 increases significantly by Gas Nitriding.
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surface hardening of biomedical ti 29nb 13ta 4 6zr and ti 6al 4v eli by Gas Nitriding
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2008Co-Authors: Masaaki Nakai, Mitsuo Niinomi, Toshikazu Akahori, Naofumi Ohtsu, Hideki Nishimura, Hiroyuki Toda, Hisao Fukui, Michiharu OgawaAbstract:Abstract The microstructure and hardness near the surface of a biomedical titanium alloy, Ti–29Nb–13Ta–4.6Zr (TNTZ), subjected to Gas Nitriding at 1023–1223 K was investigated in comparison with the conventional biomedical Ti–6Al–4V ELI (Ti64). After Gas Nitriding, the microstructure near the specimen surface was observed by optical microscopy, X-ray diffraction (XRD), Auger electron spectroscopy (AES), and X-ray photoelectron spectroscopy (XPS). In both alloys, two types of titanium nitrides (TiN and Ti 2 N) are formed and the α phase is precipitated by Gas Nitriding. Furthermore, the oxygen impurity in the Gas Nitriding atmosphere reacts with the titanium nitrides; thus, TiO 2 is formed at the outermost titanium nitride layer. The surface hardening was also evaluated by Vickers hardness measurement. The Vickers hardness near the surface of TNTZ and Ti64 increases significantly by Gas Nitriding.
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Hard-Ceramic Layer Formed on Ti-29Nb-13Ta-4.6Zr and Ti-6Al-4V ELI during Gas Nitriding
Materials Science Forum, 2007Co-Authors: Masaaki Nakai, Mitsuo Niinomi, Toshikazu Akahori, Naofumi Ohtsu, Hideki Nishimura, Hiroyuki Toda, Hisao Fukui, Michiharu OgawaAbstract:The surface of Ti-29Nb-13Ta-4.6Zr (TNTZ) subjected to Gas Nitriding at 1023–1223 K was investigated in comparison with the conventional biomedical titanium alloy, Ti-6Al-4V ELI (Ti64). After Gas Nitriding, the microstructures near the surface of these alloys were observed by optical microscopy, X-ray diffraction, Auger electron spectroscopy, and X-ray photoelectron spectroscopy. In both alloys, two titanium nitrides (TiN and Ti2N) are formed and the α phase precipitated by Gas Nitriding. Furthermore, oxygen impurity in the Gas Nitriding atmosphere reacts with the titanium nitrides; thus, TiO2 is formed at the outermost titanium nitride layer. The surface hardening was also evaluated by Vickers hardness measurement. The Vickers hardness near the surface of TNTZ and Ti64 increases significantly by Gas Nitriding.
Toshikazu Akahori - One of the best experts on this subject based on the ideXlab platform.
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Surface hardening of biomedical Ti–29Nb–13Ta–4.6Zr and Ti–6Al–4V ELI by Gas Nitriding
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2008Co-Authors: Masaaki Nakai, Mitsuo Niinomi, Toshikazu Akahori, Naofumi Ohtsu, Hideki Nishimura, Hiroyuki Toda, Hisao Fukui, Michiharu OgawaAbstract:Abstract The microstructure and hardness near the surface of a biomedical titanium alloy, Ti–29Nb–13Ta–4.6Zr (TNTZ), subjected to Gas Nitriding at 1023–1223 K was investigated in comparison with the conventional biomedical Ti–6Al–4V ELI (Ti64). After Gas Nitriding, the microstructure near the specimen surface was observed by optical microscopy, X-ray diffraction (XRD), Auger electron spectroscopy (AES), and X-ray photoelectron spectroscopy (XPS). In both alloys, two types of titanium nitrides (TiN and Ti 2 N) are formed and the α phase is precipitated by Gas Nitriding. Furthermore, the oxygen impurity in the Gas Nitriding atmosphere reacts with the titanium nitrides; thus, TiO 2 is formed at the outermost titanium nitride layer. The surface hardening was also evaluated by Vickers hardness measurement. The Vickers hardness near the surface of TNTZ and Ti64 increases significantly by Gas Nitriding.
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surface hardening of biomedical ti 29nb 13ta 4 6zr and ti 6al 4v eli by Gas Nitriding
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2008Co-Authors: Masaaki Nakai, Mitsuo Niinomi, Toshikazu Akahori, Naofumi Ohtsu, Hideki Nishimura, Hiroyuki Toda, Hisao Fukui, Michiharu OgawaAbstract:Abstract The microstructure and hardness near the surface of a biomedical titanium alloy, Ti–29Nb–13Ta–4.6Zr (TNTZ), subjected to Gas Nitriding at 1023–1223 K was investigated in comparison with the conventional biomedical Ti–6Al–4V ELI (Ti64). After Gas Nitriding, the microstructure near the specimen surface was observed by optical microscopy, X-ray diffraction (XRD), Auger electron spectroscopy (AES), and X-ray photoelectron spectroscopy (XPS). In both alloys, two types of titanium nitrides (TiN and Ti 2 N) are formed and the α phase is precipitated by Gas Nitriding. Furthermore, the oxygen impurity in the Gas Nitriding atmosphere reacts with the titanium nitrides; thus, TiO 2 is formed at the outermost titanium nitride layer. The surface hardening was also evaluated by Vickers hardness measurement. The Vickers hardness near the surface of TNTZ and Ti64 increases significantly by Gas Nitriding.
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Hard-Ceramic Layer Formed on Ti-29Nb-13Ta-4.6Zr and Ti-6Al-4V ELI during Gas Nitriding
Materials Science Forum, 2007Co-Authors: Masaaki Nakai, Mitsuo Niinomi, Toshikazu Akahori, Naofumi Ohtsu, Hideki Nishimura, Hiroyuki Toda, Hisao Fukui, Michiharu OgawaAbstract:The surface of Ti-29Nb-13Ta-4.6Zr (TNTZ) subjected to Gas Nitriding at 1023–1223 K was investigated in comparison with the conventional biomedical titanium alloy, Ti-6Al-4V ELI (Ti64). After Gas Nitriding, the microstructures near the surface of these alloys were observed by optical microscopy, X-ray diffraction, Auger electron spectroscopy, and X-ray photoelectron spectroscopy. In both alloys, two titanium nitrides (TiN and Ti2N) are formed and the α phase precipitated by Gas Nitriding. Furthermore, oxygen impurity in the Gas Nitriding atmosphere reacts with the titanium nitrides; thus, TiO2 is formed at the outermost titanium nitride layer. The surface hardening was also evaluated by Vickers hardness measurement. The Vickers hardness near the surface of TNTZ and Ti64 increases significantly by Gas Nitriding.
