Two-step diffusion treatment of aluminium-coated TiAl-based alloy

Sasaki, Tomohiro; Yagi, Takahiro

doi:10.1179/1743294415y.0000000032

Cited by 8 publications

(3 citation statements)

References 30 publications

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“…γ-TiAl alloys are widely used in aero engines and automotive components due to the outstanding creep properties (more than 900 °C), high melting point which is more than 1450 °C, and the preeminent specific modulus that is around 160 GPa to 180 GPa [1]. However, γ-TiAl alloys are limited to apply in industry because of inadequate oxidation resistance [2][3][4][5][6] . Therefore, a lot of researches were carried out to enhance the property of oxidation resistance.…”

Section: Introductionmentioning

confidence: 99%

Oxidation Behavior of Al-Y Coating on γ-TiAl at 900°C

et al. 2019

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In this study, an Al-Y coating was applied to enhance the property of oxidation resistance on the surface of γ-TiAl alloys by rf magnetron sputtering. The isothermal oxidation tests were investigated at 900 °C for 100 h. The coating characteristics and microstructure of coating after isothermal oxidation were inspected by XRD and SEM methods respectively, and coating bonding strength was investigated by scratch tester. Results show that Al 2 O 3 and Y 2 O 3 were produced on the surface of γ-TiAl alloys to enhance oxidation resistance during the isothermal oxidation test. Diffusion layer with rich element of Al provides abundant Al to surface for formation of a continuous Al 2 O 3 layer which increases oxidation resistance effectively. Oxides of YAlO 3 and YAG were formed during the oxidation tests, which were beneficial for the strength, hardness and fracture toughness of crystal grain of Al 2 O 3. Furthermore, Element of Ti diffused into surface from substrate was restrained by Al because of the formation of TiAl 3 and TiAl, which avoid the layer-broken by titanium oxides with porous structure

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Section: Introductionmentioning

confidence: 99%

Oxidation Behavior of Al-Y Coating on γ-TiAl at 900°C

et al. 2019

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“…Several researchers have prepared aluminide coatings on -TiAl alloy [6,[30][31][32][33]. The Si-modified aluminide coatings are also prepared on -TiAl alloys by pack cementation method to form titanium silicide layers on them.…”

Section: J Min Metall Sect B-metall 55 (2) B (2019) 217 -225mentioning

confidence: 99%

Microstructural investigation of the coatings prepared by simultaneous aluminizing and siliconizing process on γ-TiAl

Nouri

Azadeh

2019

J min metall B Metall

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In this research, formation of aluminide/silicide diffusion coatings on -TiAl[Ti-48Al-2Nb-2Cr (at.)] alloy using gasphase diffusion pack cementation process has been investigated. The application of powder mixtures with various chemical compositions in the pack cementation process performed at 1000 o C for 6 hours in order to achieve simultaneous diffusion of Al and Si, showed that the composition of the powder mixture could have a significant effect on the structure and thickness of the aluminide/silicide coatings. The identification and analysis of aluminide/silicide microstructures formed as a result of simultaneous diffusion of Al and Si, which was comprehensively and qualitatively done for the first time in this study, showed that the sequential mechanism is dominant in the formation of the above-mentioned coatings. Furthermore, Kirkendall phenomenon and volumetric changes caused by the formation of Ti 5 Si 3 and Ti 5 Si 4 , were considered as the two dominant mechanisms in the formation of porous segregated structure in these coatings. In this study, the effect of decreasing the activity of Si, through two approaches of reducing the amount of Si in the powder mixture and using Al-20wt.%Si alloyed powder instead of pure Al and Si depositing elements, on the microstructural modification coatings was investigated. The results showed that reducing the Si activity at the surface of the coating and, consequently, reducing the flux of active silicon atoms (J Si), has a significant effect on the formation of coating with an ideal structure.

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“…Aluminium has been established as the most acceptable structural material for aerospace industry for quite a long time [1,2]. The eminence of aluminium over other metals in aerospace specific applications is due to its superior qualities like relative abundance, lightweight and low cost [3].…”

Section: Introductionmentioning

confidence: 99%

Effect of TiN-deposition on adhesion characteristics of aluminium

Sudheendra

Kumar

Krishnan

et al. 2019

Surface Engineering

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This investigation highlights on surface modifications and adhesive bonding of aluminium. The surface of the aluminium substrate is modified by magnetron sputtering and nanoparticle reinforcements are employed into the adhesive and their effects on adhesive strength are examined. Owing to the concern of durability of the aluminium surface, adhesive joints are still questionable for their widespread use in structural applications. Various environmental conditions affect properties of adhesives and their performance may degrade over time when adhesive joints are exposed to varying moisture and temperature conditions. Modified aluminium surfaces are examined by morphological techniques to understand the result of deposition on the morphology of substrate. Surface modified samples are subjected to harsh environments and analysed by energy dispersive spectra and surface durability is quantified by corrosion penetration rate. The effect of nano-reinforcements in adhesives on bond durability is examined when the bonded joints are subjected to the harsh environment.

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Two-step diffusion treatment of aluminium-coated TiAl-based alloy

Cited by 8 publications

References 30 publications

Oxidation Behavior of Al-Y Coating on γ-TiAl at 900°C

Oxidation Behavior of Al-Y Coating on γ-TiAl at 900°C

Microstructural investigation of the coatings prepared by simultaneous aluminizing and siliconizing process on γ-TiAl

Effect of TiN-deposition on adhesion characteristics of aluminium

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