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.

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 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 Behavior of a New Directionally Solidified Ni-Base Superalloy in Air at Different Temperature

2010 ◽  
Vol 654-656 ◽  
pp. 538-541
Author(s):  
Lei Wang ◽  
Yan Huang ◽  
Zhuo Zhao ◽  
Yang Liu ◽  
Jian Tao Wu ◽  
...  
Keyword(s):  
Oxidation Resistance ◽  
Oxidation Behavior ◽  
Isothermal Oxidation ◽  
Oxidation Behaviour ◽  
Diffusion Activation Energy ◽  
Directionally Solidified ◽  
Temperature Range ◽  
Parabolic Law ◽  
Diffusion Activation ◽  
Base Superalloy

The isothermal oxidation behaviour under static atmosphere of a new directionally solidified Ni-base superalloy was investigated. The results showed that the oxidation kinetics curves of the alloy follow parabolic law in the temperature range of 750-950°C. The diffusion activation energy Q is to be about 244.86 kJ•mol-1 and the oxidation within this temperature range is mainly controlled by Cr3+ diffusion among Cr2O3 oxidation film. The oxidation resistance grade of the alloy is perfect anti-oxidation within 750-850°C, and anti-oxidation within 900-950°C. The oxidation film can be divided into TiO2, Cr2O3+TiTaO4+NiCr2O4, Al2O3 and TiN layers, from the surface to inside. Priority oxidation and the inside oxidation of Al are considered with the oxidation of Ti and the depletion of Cr, and it is the key point for the improving of oxidation resistance.

Isothermal Oxidation Behavior of Ni Base Superalloy DM02 for High Temperature Dies

2007 ◽  
Vol 546-549 ◽  
pp. 1253-1256
Author(s):  
Qing Li ◽  
Jin Xia Song ◽  
Cheng Bo Xiao ◽  
Shi Yu Qu ◽  
Ding Gang Wang ◽  
...  
Keyword(s):  
Weight Gain ◽  
High Temperature ◽  
Oxide Scale ◽  
Oxidation Resistance ◽  
Growth Mechanism ◽  
Oxidation Kinetics ◽  
Oxidation Behavior ◽  
Isothermal Oxidation ◽  
Good Oxidation Resistance ◽  
Base Superalloy

The isothermal oxidation behavior of a new developed Ni base superalloy named DM02 for high temperature dies was studied in this paper. The dynamic curve was achieved by monitoring weight gain of the alloy as a function of time. The results showed that the alloy had fairly good oxidation resistance at 1050°C and 1100°C. The oxidation kinetics at both 1050°C and 1100°C followed parabolic rules in segment. It has been found that the oxidation of the alloy was controlled by multi-oxides of (Ni, Co)O, (Ni, Co)Al2O4, and NiWO4, growth mechanism in the primary stage, and by Al2O3, NiAl2O4 growth mechanism in the following stage. After oxidation at 1050°C for 100h, the oxide scale of the alloy was mainly composed of two areas. Some were thin uniform (Ni， Co)Al2O4(outer)/Al2O3 (inner) composites scale and others were multi-layer oxide scale of ( Ni,Co)O / multi-oxides (mainly NiWO4、NiO and NiAl2O4.) /Al2O3.

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.

Oxidation Behavior of NiAl Produced by Gel Combustion Synthesis

2016 ◽  
Vol 701 ◽  
pp. 122-126
Author(s):  
Tammy Anne Gonsalvez ◽  
Abreeza Manap ◽  
Nurfanizan Afandi ◽  
Halina Misran
Keyword(s):  
Combustion Synthesis ◽  
Oxidation Behavior ◽  
Mixed Oxides ◽  
Synthesis Method ◽  
Mass Gain ◽  
Isothermal Oxidation ◽  
X Ray Diffraction ◽  
Gel Combustion ◽  
Before And After ◽  
Different Temperatures

This paper presents the results of a study of the oxidation behavior of NiAl produced by gel combustion synthesis calcined at two different temperatures. The objective is to compare the oxide growth rates, oxide scale composition, morphology and elemental composition of the sample powder subjected to isothermal oxidation and calcined at 1050 °C and 1300 °C for 1, 2, 4 and 10 hours by means of mass gain measurements, X-ray diffraction (XRD), field emission scanning electron microsocopy (FESEM) and energy-dispersive spectrometry (EDX) in order to investigate the reliability of the gel combustion synthesis method and evaluate the effect of calcination temperature on the oxidation behaviour of the powder. It was found that for the sample calcined at 1300°C the sample was made up mainly of metastable and stable alumina before oxidation and stable alpha alumina after oxidation whereas for the powder calcined at 1050°C the sample was mainly composed of detrimental mixed oxides before and after oxidation. Overall findings indicate that the oxidation behavior of the powder calcined at 1300°C is more protective compared to the powder calcined at 1050°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.

scholarly journals Oxidation Behavior of Refractory AlNbTiVZr0.25 High-Entropy Alloy

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2526 ◽  
Author(s):  
Nikita Yurchenko ◽  
Evgeniya Panina ◽  
Sergey Zherebtsov ◽  
Gennady Salishchev ◽  
Nikita Stepanov
Keyword(s):  
Oxidation Kinetics ◽  
Oxidation Behavior ◽  
High Entropy Alloy ◽  
X Ray Diffraction ◽  
Breakaway Oxidation ◽  
High Entropy ◽  
Second Stage ◽  
Entire Duration ◽  
Different Temperatures ◽  
Oxidation Mechanisms

Oxidation behavior of a refractory AlNbTiVZr0.25 high-entropy alloy at 600–900 °C was investigated. At 600–700 °C, two-stage oxidation kinetics was found: Nearly parabolic oxidation (n = 0.46–0.48) at the first stage, transitioned to breakaway oxidation (n = 0.75–0.72) at the second stage. At 800 °C, the oxidation kinetics was nearly linear (n = 0.92) throughout the entire duration of testing. At 900 °C, the specimen disintegrated after 50 h of testing. The specific mass gains were estimated to be 7.2, 38.1, and 107.5, and 225.5 mg/cm2 at 600, 700, and 800 °C for 100 h, and 900 °C for 50 h, respectively. Phase compositions and morphology of the oxide scales were analyzed using X-ray diffraction (XRD) and scanning electron microscopy (SEM). It was shown that the surface layer at 600 °C consisted of the V2O5, VO2, TiO2, Nb2O5, and TiNb2O7 oxides. Meanwhile, the scale at 900 °C comprised of complex TiNb2O7, AlNbO4, and Nb2Zr6O17 oxides. The oxidation mechanisms operating at different temperatures were discussed and a comparison of oxidation characteristics with the other alloys was conducted.

Effects of Si Content on the Oxidation Behavior of Fe–Si Alloys in Air

2011 ◽  
Vol 696 ◽  
pp. 126-131 ◽  
Author(s):  
Takumi Nishimoto ◽  
Kazuhiko Honda ◽  
Yasumitsu Kondo ◽  
Kenichi Uemura
Keyword(s):  
Oxide Scale ◽  
Cross Sections ◽  
Oxidation Kinetics ◽  
Oxidation Behavior ◽  
Elemental Distribution ◽  
Oxide Scales ◽  
Scale Thickness ◽  
Internal Oxidation Zone ◽  
Diffusion Controlled ◽  
Si Content

The oxidation behavior of Fe–Si alloys at 1073K in air was investigated. The oxidation kinetics described by the parabolic rate law of diffusion controlled oxidation and the oxidation rate decrease with the increasing Si content. Fe-Si alloys were oxidized for different times at 1073K to obtain the same scale thickness of approximately 30μm. Observations of scale cross-sections indicated the structure of oxide scale and elemental distribution in oxide scales strongly depends on Si content. The oxide scale on Fe-Si alloys with low Si content consisted of three layers with an outer Fe2O3, an intermediate Fe3O4 and an inner FeO and some voids were formed in Fe3O4 and FeO layers. The Si-rich oxide layer was formed at the scale/alloy interface of Fe-Si alloys with high Si content. Furthermore, the amount of internal oxidation zone increased with the increasing Si content. Observations of scale cross-sections indicated that the structure of oxide scale and elemental distribution in oxide scale strongly depend on Si content.

scholarly journals Investigation on Optimal Ta/Cr Ratio of a Single Crystal Ni-Base Superalloy in View of the Isothermal Oxidation Behavior

Crystals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1421
Author(s):  
Jianxiu Chang ◽  
Wenhao Feng ◽  
Wenwen Zhao ◽  
Hongmin Jia ◽  
Yanming Liu ◽  
...  
Keyword(s):  
Single Crystal ◽  
Oxidation Resistance ◽  
Oxidation Behavior ◽  
Isothermal Oxidation ◽  
Nitride Layer ◽  
Oxidation Products ◽  
Competitive Growth ◽  
X Ray Diffraction ◽  
Al2o3 Layer ◽  
Oxidation Performance

The relative content of strengthening element tantalum (Ta) and oxidation-resistant element chromium (Cr) is an essential value for superalloys to obtain an excellent combination of oxidation resistance and mechanical properties. In the present paper, the isothermal oxidation behavior of several single crystal Ni-base superalloys with different Ta/Cr (wt. %, similarly hereinafter) ratios at 1000 °C in static air has been systematically investigated to explore the optimal Ta/Cr for excellent oxidation resistance. A detailed microstructure study using X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) and an electro-probe microanalyzer (EPMA) was performed to reveal the oxidation products and mechanisms. For all alloys, a three-layer structured scale consisting of an outer (Cr, Al, Ti, Ni, Ta)-O layer, an inner Al2O3 layer and an inner nitride layer was formed. As Ta/Cr increased, the amounts of Ta-containing products, cracks, holes and inner nitride increased. Meanwhile, the completeness of the Al2O3 layer got worse. It was shown that if Ta/Cr ≤ 0.5, Ta increased the growth rate of Cr2O3 via the doping effect induced by Ta cations. If Ta/Cr > 0.5, Ta reduced the completeness of Cr2O3 through competitive growth of Ta2O5 and Cr2O3. A good oxidation performance can be expected with the value Ta/Cr ≤ 0.5.

Sign in / Sign up

Export Citation Format

Share Document