Isothermal Oxidation Behavior of FGH720Li Superalloy at Service Temperatures

2021 ◽  
Vol 1035 ◽  
pp. 96-101
Author(s):  
Yue Tang ◽  
Zi Chao Peng ◽  
Xu Qing Wang ◽  
Guo Jun Ma ◽  
Dan Wu
Keyword(s):  
Oxidation Kinetics ◽  
Oxidation Behavior ◽  
Isothermal Oxidation ◽  
Elemental Distribution ◽  
X Ray Diffraction ◽  
Cross Sectional ◽  
X Ray ◽  
Parabolic Law ◽  
Medium Layer ◽  
Oxidation Layers

The oxidation behavior of FGH720Li(P/M Udimet720Li) superalloy was investigated under static atmosphere in temperature ranging from 600°C to 730°C. The oxidation kinetics, composition and morphology of the oxidation layers were characterized by means of isothermal oxidation tests, X-ray diffraction(XRD), scanning electron microscopy（SEM）and energy dispersive X-ray spectroscopy(EDS). The results showed that the oxidation kinetics curves of FGH720Li superalloy followed the parabolic law. The results of cross-sectional morphology and elemental distribution indicated that the oxidation layer could be divided into three parts：porous Cr2O3 outer layer, dense Cr2O3 medium layer and oxidation affected zone with nail-like Al2O3 inner layer. The oxidation process was primarily controlled by the diffusion of chromium and oxygen through the oxide scale.

Isothermal oxidation of bulk Zr2Al3C4 at 500 to 1000 °C in air

2008 ◽  
Vol 23 (2) ◽  
pp. 359-366 ◽  
Author(s):  
L.F. He ◽  
Z.J. Lin ◽  
Y.W. Bao ◽  
M.S. Li ◽  
J.Y. Wang ◽  
...  
Keyword(s):  
Activation Energy ◽  
Raman Spectra ◽  
Oxidation Kinetics ◽  
Oxidation Behavior ◽  
Oxygen Affinity ◽  
Isothermal Oxidation ◽  
Oxide Scales ◽  
X Ray Diffraction ◽  
X Ray ◽  
Parabolic Law

The isothermal oxidation behavior of Zr2Al3C4 in the temperature range of 500 to 1000 °C for 20 h in air has been investigated. The oxidation kinetics follow a parabolic law at 600 to 800 °C and a linear law at higher temperatures. The activation energy is determined to be 167.4 and 201.2 kJ/mol at parabolic and linear stages, respectively. The oxide scales have a monolayer structure, which is a mixture of ZrO2 and Al2O3. As indicated by x-ray diffraction and Raman spectra, the scales formed at 500 to 700 °C are amorphous, and at higher temperatures are α-Al2O3 and t-ZrO2 nanocrystallites. The nonselective oxidation of Zr2Al3C4 can be attributed to the strong coupling between Al3C2 units and ZrC blocks in its structure, and the close oxygen affinity of Zr and Al.

Isothermal Oxidation Behavior of the AISI430 Stainless Steel at High Temperature in Static Air

2011 ◽  
Vol 306-307 ◽  
pp. 95-99
Author(s):  
Bin Sun ◽  
Shou Ren Wang ◽  
Yan Jun Wang ◽  
Yong Zhi Pan
Keyword(s):  
Stainless Steel ◽  
High Temperature ◽  
Outer Layer ◽  
Oxidation Behavior ◽  
Isothermal Oxidation ◽  
Chemical Analyses ◽  
X Ray Diffraction ◽  
X Ray ◽  
Chromium Spinel ◽  
Anomalous Oxidation

Isothermal oxidation behavior of the AISI430 stainless steel was investigated at 900°C and 950°C in air. Isothermal themogravimettric analyses were performed at high-temperature for 360ks (kilo-seconds). The microstructures of the oxide films on the stainless steel were characterized by SEM and chemical analyses were performed by EDS and X-ray diffraction. The oxide film included outer layer and inner one. The outer layer was magnetite and hematite oxides with no significant amounts of chromium and the inner one was formed by iron and chromium spinel. Significantly accelerated and anomalous oxidation was observed with the stainless steel AISI430 in air at 900°C.

Investigating the High Temperature Oxidation Behavior of TiAl-Based Alloys with Nickel and Ruthenium Additions

2014 ◽  
Vol 1019 ◽  
pp. 294-301
Author(s):  
H.C. Mantyi ◽  
L.A. Cornish ◽  
Lesley H. Chown ◽  
I. Alain Mwamba
Keyword(s):  
Room Temperature ◽  
Oxidation Behavior ◽  
Mass Gain ◽  
Isothermal Oxidation ◽  
X Ray Diffraction ◽  
Mechanically Alloyed ◽  
Temperature Oxidation ◽  
X Ray ◽  
High Temperature Oxidation Behavior ◽  
Titanium Aluminium

Pure powders of titanium, aluminium, nickel and ruthenium were mechanically alloyed and melted in a button arc furnace under an argon atmosphere to produce two alloys of composition Ti-52.5Al-10.0Ni (at.%) and Ti-52.5Al-10.0Ni-0.2Ru (at.%). The alloys were then cut and metallographically prepared. Scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD) were used to characterize the samples. Thermogravimetric analysis (TGA) was used to analyze the oxidation behavior from room temperature up to 1050°C. The alloys were also oxidized in air at 1050°C for 120 hours. The Ti-52.5Al-10.0Ni (at.%) alloy formed dendrites of γ-TiAl (55.6 at.% Al) surrounded by a eutectic of γ-TiAl + Al3NiTi2 (τ3) phases. The Ti-52.5Al-10.0Ni-0.2Ru (at.%) alloy formed dendrites of γ-TiAl (53.6 at.% Al) surrounded by a eutectic of γ-TiAl + Al3NiTi2 (τ3). The ruthenium was mostly in solid solution (0.3 at.%) in the Al3NiTi2 (τ3) phase, although traces of it were present in the dendrites (0.1 at.% Ru). When oxidized in air from room temperature to 1050°C, the as-cast Ti-52.5Al-10.0Ni-0.2Ru (at.%) had a mass gain of 0.60% and the as-cast Ti-52.5Al-10.0Ni (at.%) had a mass gain of 0.97%. Isothermal oxidation of both alloys at 1050°C for 120 hours formed mixed metal oxides of TiO2+Al2O3 on the surface.

Research on the Si-Ti High Temperature Oxidation-Resistant Coatings for Tantalum Alloys

2013 ◽  
Vol 785-786 ◽  
pp. 45-51
Author(s):  
Pei Pei Song ◽  
Jun Le ◽  
Feng Ye ◽  
Xiao Cheng Sheng ◽  
Xiao Wei Zhang
Keyword(s):  
High Temperature ◽  
High Temperature Oxidation ◽  
Isothermal Oxidation ◽  
X Ray Diffraction ◽  
Cross Sectional ◽  
Temperature Oxidation ◽  
X Ray ◽  
Different Temperatures ◽  
Slurry Method ◽  
Sectional Structure

Si-Ti coatings were prepared on the surface of T-222 alloy by fused slurry method at different temperatures (1425-1500°C). Microstructure and composition of the coatings were characterized and analysed through scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), energy dispersive X-ray spectrometry (EDS) respectively. The coating fabricated at 1450°C exhibited excellent structure compatible with high temperature oxidation resistance. Its surface is relatively smooth with few holes and cracks and the main phase on the surface is (Ti, Ta)Si that possesses outstanding corrosion resistance. Moreover, the cross-sectional structure of the coating is smooth and compact which can effectively prevent O2 from permeation. The isothermal oxidation behaviors in pure O2 atmosphere at 1500°C for 2h finally demonstrate that the optimum coating temperature is 1450°C.

scholarly journals Isothermal Oxidation Behavior of Novel Al2O3 / NiCrAlY / Ti3Al System at 850�C

2020 ◽  
Vol 71 (5) ◽  
pp. 106-116
Author(s):  
Alexandra Banu ◽  
Alexandru Paraschiv ◽  
Simona Petrescu ◽  
Irina Atkinson ◽  
Elena Maria Anghel ◽  
...  
Keyword(s):  
Oxidation Resistance ◽  
Oxidation Behavior ◽  
Mass Gain ◽  
Isothermal Oxidation ◽  
Thermal Barrier ◽  
The Novel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Aerospace Applications

The novel Al2O3 / NiCrAlY /alfa2-Ti3Al system obtained by APS technique was tested against long (500h) isothermal oxidation at 850�C in air for prospective use in aerospace applications. EDX-SEM, X-ray diffraction (XRD) and Raman investigations were conducted to substantiate structural, textural and mass gain modifications underwent by the Al2O3 / NiCrAlY /alfa2-Ti3Al system in comparison with bare alfa2-Ti3Al and NiCrAlY /alfa2-Ti3Al system. Improved oxidation resistance of the double-coated system is based on moderate oxygen and thermal barrier role played by the mixture of delta - and alfa-Al2O3 present in the top ceramic coat.

Study of Isothermal Oxidation Behavior of FGH91 Superalloy

2015 ◽  
Vol 816 ◽  
pp. 628-633 ◽  
Author(s):  
Zi Chao Peng ◽  
Guo Jun Ma ◽  
Xu Qing Wang ◽  
Xue Jun Luo
Keyword(s):  
Activation Energy ◽  
Titanium Nitride ◽  
Outer Layer ◽  
Oxidation Kinetics ◽  
Intermediate Layer ◽  
Oxidation Behavior ◽  
Matrix Alloy ◽  
Isothermal Oxidation ◽  
Free Layer ◽  
Parabolic Law

Oxidation behavior of FGH91 superalloy in air and the temperature range of 540 to 980 °C for period up to 100h has been studied. The results indicate that oxidation kinetics obeyed parabolic law, and the activation energy of oxidation was calculated to be 98.2 KJ/mol. The scales on the surface were determined by SEM, EDS and XRD, the results show that the oxidation scales were composed of three layers: the outer layer was composed of Cr2O3 layer with a small amount of TiO and NiCr2O4 spinel; the intermediate layer was made up of Al2O3 and matrix alloy; and a small amount of titanium-nitride disperse in the inner layer. Besides, γ’-free layer was formed under the oxidation scales due to the impoverishment of Al in this layer, which was induced by the formations of Al2O3.

scholarly journals High-Temperature Oxidation Behavior and Kinetics of Forged 12Cr-MoVW Steel

2017 ◽  
Vol 62 (2) ◽  
pp. 1099-1104
Author(s):  
Yong Hwan Kim ◽  
Jeong-Jung Oak ◽  
Ki-Chang Bae ◽  
Wook Jin Lee ◽  
Yong Ho Park
Keyword(s):  
High Temperature Oxidation ◽  
Oxidation Behavior ◽  
X Ray Diffraction ◽  
Protective Oxide ◽  
Cross Sectional ◽  
Temperature Oxidation ◽  
Protective Oxide Layer ◽  
X Ray ◽  
High Temperature Oxidation Behavior ◽  
Kinetics Of

AbstractThe oxidation kinetics of forged 12Cr-MoVW steel was investigated in an air (N2+O2) atmosphere at 873-1073 K (Δ50 K) using thermogravimetric analysis. The oxidized samples were characterized using X-ray diffraction, and the surface and cross-sectional morphologies were examined using scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy. The forged 12Cr-MoVW steel samples exhibited parabolic behavior and a low oxidation rate compared with their as-cast counterparts. A protective oxide layer was uniformly formed at relatively low temperature (≤973 K) for the forged samples, which thus exhibited better oxidation resistance than the as-cast ones. These oxides are considered solid-solution compounds such as (Fe, Cr)2O3.

Oxidation Behaviour of Intermetallic Compounds Based on Ti-Al System

1994 ◽  
Vol 364 ◽  
Author(s):  
A. Tomasi ◽  
S. Gialanella ◽  
P. G. Orsini ◽  
M. Nazmy
Keyword(s):  
Oxidation Kinetics ◽  
Fixed Time ◽  
Isothermal Oxidation ◽  
Operating Conditions ◽  
Weight Changes ◽  
X Ray Diffraction ◽  
Time Intervals ◽  
Surface Stability ◽  
X Ray ◽  
The Stability

AbstractIn this study we present some results regarding phase and surface stability, with particular reference to the oxidation, of Ti alloys based on the γ-TiAl phase.We investigated the stability of the metallic phases with TG and DSC methods, according to the temperature range over which the relevant transformations do occur. These tests were particularly useful to select times and temperatures for precipitation hardening treatments and also to evaluate the oxidation resistance.The isothermal oxidation kinetics were followed with a thermobalance (TG) for time up to 25 hours and, for longer treatments, we put the samples in a furnace and measured their weight changes at fixed time intervals. The microstructure of the oxide scale was investigated with scanning electron microscopy and energy dispersion X-ray analysis and mapping. The identification of the crystalline phases was carried out with X-ray diffraction analysis.The obtained results afford clear information on the predominant phenomena assisting the observed oxidation kinetics and give indications on the operating conditions suitable for these materials.

Oxidation Behavior of a Disk Powder Metallurgy Superalloy

2017 ◽  
Vol 898 ◽  
pp. 467-475
Author(s):  
Kai Xin Dong ◽  
Chao Yuan ◽  
Shuang Gao ◽  
Jian Ting Guo
Keyword(s):  
Oxidation Kinetics ◽  
Oxidation Behavior ◽  
Isothermal Oxidation ◽  
Spray Forming ◽  
X Ray Diffraction ◽  
Temperature Range ◽  
Scale Thickness ◽  
Aluminum Ions ◽  
Gain Measurement ◽  
Oxidation Behaviors

Oxidation behaviors of a spray-forming disk superalloy LSHR were investigated in the temperature range of 750-900°C. The composition and morphology of oxidation scales were investigated by X-ray diffraction (XRD), scanning electron microscopy equipped with energy dispersive spectroscopy (SEM-EDS), and electron probe microanalysis (EPMA). Oxidation kinetics was studied by the means of isothermal oxidation testing in air and weight gain measurement. The oxide scales were composed of Cr2O3, TiO2, Al2O3 and a small amount of NiCr2O4. The experiment results showed that oxidation kinetics and oxide layers followed a square power law as time extended from 750 to 900°C. With the oxidation temperature increasing, external scale thickness, and internal oxidation zone increased. The oxidation behavior was controlled by the diffusion of oxygen, chromium, titanium, and aluminum ions, as chromium, titanium, and aluminum ions diffused outward and oxygen diffused inward. Based on the standard HB5258-2000 spray-forming LSHR exhibited an excellent oxidation resistance in the whole test temperature range.

Oxidation Behaviour of WE54 and Elektron 21 Magnesium Alloys

2011 ◽  
Vol 312-315 ◽  
pp. 483-488 ◽  
Author(s):  
Andrzej Kiełbus ◽  
Tomasz Rzychoń ◽  
Roman Przeliorz
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Oxidation Kinetics ◽  
Oxidation Behaviour ◽  
X Ray Diffraction ◽  
X Ray ◽  
Parabolic Law ◽  
Supersaturated State ◽  
Kinetics Of ◽  
Scanning Electron

In the present study, the isothermal early oxidation behaviour of the WE54 and Elektron 21 alloys were studied at a temperature of 773 K in pure O2 up to 150 min. The results showed that the oxidation kinetics depending on the chemical composition and microstructure of the investigated alloys. The oxidation kinetics of these alloys in as-cast and T6 conditions obtained a parabolic law, while in supersaturated state these alloys exhibited a linear kinetics. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses indicated that an oxide film, composed of MgO and (Y,Dy)2O3 in WE54 alloy and (Nd,Gd)2O3 in Elektron 21 alloy, had been formed.

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