Evaluation of growth kinetics of aluminide coating layers on Ti-6Al-4V alloys by pack cementation and the oxidation behaviours of the coated Ti-6Al-4V alloys

Yang, Wonchul; Park, Jinsoo; Choi, Kwang-Soo; Chung, Choong‐Heui; Lee, Jongwon; Zhu, Jun; Zhao, Fan; Park, Joon Sik

doi:10.1016/j.ijrmhm.2021.105642

Cited by 12 publications

(4 citation statements)

References 24 publications

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“…The relationship between the free energy magnitudes of TiAl, TiAl2, and TiAl3 formation in the temperature range of 273 to 1473 K followed an order of ΔG(TiAl) > ΔG(TiAl3) > ΔG(TiAl2) [38,39]. Therefore, the reactive diffusion of active Al atoms in the matrix alloy predominantly formed TiAl2 phase (reaction (3) and Figure 7(a)).…”

Section: Formation Of the Coating Structurementioning

confidence: 98%

Structure and High-Temperature Oxidation Properties of an Al-Co-Y diffusion Coating prepared on TiAl-Nb alloy at a Low Temperature

Li,

Wei,

et al. 2023

Preprint

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An Al-Co-Y diffusion coating was prepared on a TiAl alloy by pack cementation process at a low temperature range of 650-720 ℃. The influence of different activators and co-deposition temperatures on the coating’s microstructure and formation process, and high temperature oxida-tion performance was studied. The results showed that NaF was a more suitable activator for preparing the Al-Co-Y diffusion coating on TiAl alloy compared to NH4Cl and AlCl3. A more compact coating structure can be obtained when deposition was performed at 680 ℃ using NaF as the activator. The coating was mainly composed of a TiAl3 outer layer, a TiAl2 inner layer, and a thin Al-rich TiAl inter-diffusion layer. The growth of the coating exhibited a positive linear correlation between coating thickness increase and the square root of deposition time. The high-temperature oxidation tests showed that a dense scale mainly composed of Al2O3 and a small amount of TiO2 formed on the coating after oxidation at 950 ℃ for 100 h. The scale possessed excellent high-temperature oxidation resistance, with a parabolic rate constant of the oxidation weight gain approximately 4.9×10-3 mg2/cm4 h, which is lower than that of the TiAl substrate by about three orders of magnitude, and lower than that of the pure Al diffusion coating more than one order of magnitude.

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Section: Formation Of the Coating Structurementioning

confidence: 98%

Structure and High-Temperature Oxidation Properties of an Al-Co-Y diffusion Coating prepared on TiAl-Nb alloy at a Low Temperature

Li,

Wei,

et al. 2023

Preprint

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“…After hot-dip aluminizing, the coating formed on the surface of the Ti65 sample is composed of the TiAl 3 phase +L-(Ti,Al) and L-(Ti,Al) layer. The relationship between the thickness and time of the TiAl 3 phase can be expressed by the empirical formula [28,29]:…”

Section: Growth Kinetics Of the Tial 3 Phasementioning

confidence: 99%

Study on the Effect of Carburizing on the Microstructure and High-Temperature Oxidation Properties of Hot-Dip Aluminum Coating on Titanium Alloy

Yang,

2023

Coatings

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A Ti–Al alloy phase layer/Ti–Al carburizing composite coating was prepared on the surface of titanium alloy by the stepwise coating method of hot-dip aluminizing and then carburizing. The weight gain results of the composite coating showed that the titanium alloy coated with the composite coating had long-term stability (≥16 days) at 800 °C. The microstructure, phase structure, and composition of the composite coating were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). The composite coating is composed of an alloy phase layer and a carburized layer. The natural transition of four phases (Ti3Al/TiAl/TiAl2/TiAl3) in the alloy phase layer significantly improves the interfacial bonding between the coating and the substrate and slows down the propagation of microcracks through the coating. Al2O3, TiC, and C in the carburizing layer improve the surface hardness of the coating, and TiAl2 and Al2O3 also have excellent oxidation resistance at high temperature.

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“…The use of α 2 -Ti 3 Al and γ-TiAl alloys can be a solution to the oxidation resistance problem, however, their practical use is limited by poor room temperature ductility and the susceptibility to brittle fracture. From this point of view, the application of coatings containing these phases on the titanium alloy can be advantageous [4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Cyclic oxidation of slurry silicide-aluminide coatings formed on Ti-6Al-4V alloy

Kochmańska,

Kochmański

2023

Surface Engineering

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A proprietary slurry cementation method was used to produce silicide-aluminide coatings on alloy Ti-6Al-4V. The cementation processes were carried out at 900-1100 °C for 2-6 h. The coatings exhibited a stratified configuration characterised by a phase arrangement that demonstrates favourable attributes pertaining to mechanical and corrosion resistance capabilities, namely, the presence of aluminium-enriched phases at the coating surface and titanium-enriched phases proximity to the substrate. The cyclic oxidation behaviour at 800 °C for 30 twenty-two-hour cycles was investigated. The characterisation of the structure of coatings was carried out through the use of scanning microscopy, X-ray microanalysis, and Xray diffraction techniques. The coatings have excellent resistance to cyclic oxidation, resulting from the gradient structure and the establishment of a protective alumina layer on the surface. The coatings were characterised by good resistance to thermal shocks. The microcracks formed during thermal shocks were filled with an alumina, which renders the coatings self-healing.

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Evaluation of growth kinetics of aluminide coating layers on Ti-6Al-4V alloys by pack cementation and the oxidation behaviours of the coated Ti-6Al-4V alloys

Cited by 12 publications

References 24 publications

Structure and High-Temperature Oxidation Properties of an Al-Co-Y diffusion Coating prepared on TiAl-Nb alloy at a Low Temperature

Structure and High-Temperature Oxidation Properties of an Al-Co-Y diffusion Coating prepared on TiAl-Nb alloy at a Low Temperature

Study on the Effect of Carburizing on the Microstructure and High-Temperature Oxidation Properties of Hot-Dip Aluminum Coating on Titanium Alloy

Cyclic oxidation of slurry silicide-aluminide coatings formed on Ti-6Al-4V alloy

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