Structure and High-Temperature Oxidation of Ti-Al-Nb and Ti-Al-Ta Intermetallics

2011 ◽  
Vol 465 ◽  
pp. 227-230 ◽  
Author(s):  
Dalibor Vojtěch ◽  
Tomáš Popela
Keyword(s):  
High Temperature ◽  
Oxidation Resistance ◽  
Oxidation Mechanism ◽  
High Strength ◽  
Vacuum Arc ◽  
Temperature Oxidation ◽  
Good Oxidation Resistance ◽  
Arc Melting ◽  
Vacuum Arc Melting ◽  
Work Structure

Ti-Al based intermetallics are prospective high-temperature materials showing low weight combined with a relatively high strength, high creep resistance and good oxidation resistance at high temperatures. Beside Ti and Al, these materials commonly contain other additives modifying their properties. In the present work, structure and oxidation resistance of two Ti-Al-Nb and Ti-Al-Ta alloys are studied. The alloys are prepared by vacuum arc melting and oxidation is conducted in air at 800-1000°C. It is found that there are significant differences in the structure depending on the ternary additive. There are also differences in oxidation behavior and these differences are discussed in relation to oxidation mechanism.

scholarly journals Microstructure and Oxidation Resistance of Cr–Al–Si Alloys for High-Temperature Applications

Coatings ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 329
Author(s):  
Jeong-Min Kim ◽  
Chae-Young Kim
Keyword(s):  
High Temperature ◽  
Oxidation Resistance ◽  
Single Phase ◽  
Melting Furnace ◽  
Vacuum Arc ◽  
Coating Materials ◽  
Temperature Oxidation ◽  
Al Content ◽  
Arc Melting ◽  
Vacuum Arc Melting

Cr–Al alloys are attracting much attention as heat- and corrosion-resistant coating materials due to their excellent high-temperature properties. In order to investigate the effect of aluminum content on the microstructure and oxidation resistance of Cr–Al–Si alloys, cast specimens were prepared by using a vacuum-arc melting furnace, and high-temperature oxidation tests were conducted with the specimens, for 1 h, at 1100 °C, in air. In the case of cast microstructure of Cr–Al–Si alloys, it consists mainly of Cr single phase, up to 5 at.% Al, and AlCr phases were additionally formed in alloys containing 10% Al or more. In the specimen with 20% Al added, CrSi phase was also found in addition to the AlCr phase. The weight change of the specimens heated for 1 h, at 1100 °C, indicated that all had excellent oxidation resistance. However, when the Al content was less than 10%, the weight gain tended to be a little lower than that of 10% or more.

Alloying Element Ta Effect on Microstructure of Co-Al-W Superalloy by Vacuum Arc Melting

2013 ◽  
Vol 718-720 ◽  
pp. 10-13
Author(s):  
Wen Jun Zhao ◽  
Yang Tao Xu
Keyword(s):  
High Temperature ◽  
High Strength ◽  
Vacuum Arc ◽  
High Temperature Strength ◽  
The Novel ◽  
Alloying Element ◽  
Arc Melting ◽  
Vacuum Arc Melting ◽  
Before And After ◽  
Nickel Base

Co-based high temperature alloys have been widely used in aeronautics and astronautics industry, because of its high strength at high temperature, excellent resistance of hot corrosion and oxidation. Unlike the traditional Co-based superalloys, strengthened by solution and carbide strengthening, the novel Co-Al-W superalloys are strengthened by a ternary compound with the Ll2 structure γ-Co3(Al,W). And the novel Co-Al-W superalloys showing high-temperature strength greater than those of conventional nickel-base superalloys, will become the candidates for next-generation high-temperature materials. We research alloying element Ta effect on microstructure of Co-Al-W superalloys by vacuum arc melting. Compare with the microstructure before and after adding alloying element Ta of Co-Al-W superalloy, we find that most of Ta element distributed in the γ-Co substrate phase, stabilizing and reinforcement the γ phase.

Effect of B on the Microstructures and High Temperature Oxidation Resistance of a Nb-Si System In Situ Composite

2007 ◽  
Vol 546-549 ◽  
pp. 1489-1494 ◽  
Author(s):  
Ai Qin Liu ◽  
Shu Suo Li ◽  
Lu Sun ◽  
Ya Fang Han
Keyword(s):  
High Temperature ◽  
Oxide Scale ◽  
Oxidation Resistance ◽  
High Temperature Oxidation ◽  
Temperature Oxidation ◽  
X Ray ◽  
Solid Solution Strengthening ◽  
Arc Melting ◽  
The Matrix

Nb-16Si-24Ti-6Cr-6Al-2Hf-xB(x=0, 0.5, 1, 2, 4, 6) in situ composites were prepared by arc-melting. Microstructure and the effect of boron on 1250C oxidation resistance of the composites were investigated by scanning electron microscopy(SEM) and X-ray energy disperse spectrum(EDS) as well as X-ray diffraction(XRD). The experimental results showed that the high temperature oxidation resistance of the alloy was remarkably improved by adding proper amount of boron. This may be resulted from several beneficial roles of boron, i.e., boron improves the resistance of Nb5Si3 by solid solution strengthening, inhibits the diffusion of oxygen in the matrix, improves the adherence between the oxide scale and the substrate and increases the cracking resistance of the oxide scale.

Edge-on TEM studies of oxide scale formation on FeNiCr alloys

1984 ◽  
Vol 42 ◽  
pp. 612-615
Author(s):  
S.B. Newcomb
Keyword(s):  
High Temperature ◽  
Oxidation Resistance ◽  
Lattice Diffusion ◽  
Temperature Oxidation ◽  
Outward Diffusion ◽  
Temperature Growth ◽  
Good Oxidation Resistance ◽  
Thermally Activated ◽  
Chromium Alloys ◽  
State Scale

The high temperature oxidation resistance of many commercial alloy systems is often reliant upon the development of a steady state scale via the selective oxidation of one of the alloy constituents. The growth of adherent chromiumrich sesquioxides on iron-chromium alloys, for example, imparts good oxidation resistance although steels of low chromium content (< 13wt%) generally form thick layered scales which may breakdown after extended periods giving rise to accelerated rates of oxidation. The high temperature growth process essentially proceeds thermally activated transport and may involve either the outward diffusion of cations and/or the inward migration of anions. Typically, solid state diffusional transport will take place by lattice diffusion or by transport along grain boundaries so that the overall rate of transport is an inherent property of the oxide structure and composition. Equally, the morphology of the oxide itself will be determined by a variety of kinetic and thermodynamic factors.

Application of Silicon for a Protection of Titanium against High-Temperature Oxidation

2005 ◽  
Vol 482 ◽  
pp. 243-246 ◽  
Author(s):  
Dalibor Vojtěch ◽  
Tomáš Kubatík ◽  
Hana Čížová
Keyword(s):  
High Temperature ◽  
Oxidation Resistance ◽  
High Temperature Oxidation ◽  
Cyclic Oxidation ◽  
Oxidation Mechanism ◽  
Positive Influence ◽  
Surface Alloying ◽  
Temperature Oxidation

The paper describes a positive influence of silicon on the high-temperature oxidation resistance of titanium. Since silicon additions can be realized both by bulk and by surface alloying, the surface siliconizing techniques, as well as structure of the Si-rich layers, are illustrated. Furthermore, the high-temperature cyclic oxidation resistance of the surface siliconized titanium and of the TiSi2 alloy are compared to that of pure Ti and TiAl6V4 alloy, and the oxidation mechanism is discussed.

Improvement of high-temperature initial oxidation behavior of HR3C austenitic heat-resistant steel using silicon modification: experimental and first-principle study

2019 ◽  
Vol 116 (4) ◽  
pp. 401
Author(s):  
Tao Gao ◽  
Jian Wang ◽  
Nan Dong ◽  
Peide Han
Keyword(s):  
High Temperature ◽  
Oxidation Resistance ◽  
Oxidation Mechanism ◽  
Optical Emission ◽  
Energy Dispersive Spectrum ◽  
X Ray Diffraction ◽  
Initial Oxidation ◽  
Temperature Oxidation ◽  
The Matrix ◽  
The Stability

A novel silicon-containing austenitic stainless steel with excellent high-temperature initial oxidation resistance was prepared by adding 2.5 wt.% Si and modifying composition of the HR3C steels. Compared with HR3C steel, the oxidation resistance property of the steels containing silicon was markedly better at 800 °C. The high temperature oxidation mechanism of the steels containing silicon was analyzed by using scanning electron microscopy (SEM) with energy-dispersive spectrum (EDS) system, X-ray diffraction (XRD), glow discharge optical emission spectroscopy (GDOES), and first-principles calculations. The results show that the Si atom in the 22Cr-25Ni-2.5Si steel initially diffused from the matrix to the surface and then reacted with O2 to form SiO2. The SiO2 had an inhibiting effect on the diffusion of Cr from matrix resulting in maintenance of the stability of the oxidation film and improvement of the oxidation resistance as compared with the HR3C.

scholarly journals High Temperature Oxidation Behaviors of BaO/TiO2 Binary Oxide-Enhanced NiAl-Based Composites

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6510
Author(s):  
Bo Li ◽  
Ruipeng Gao ◽  
Hongjian Guo ◽  
Congmin Fan
Keyword(s):  
High Temperature ◽  
Oxidation Resistance ◽  
High Temperature Oxidation ◽  
Oxidation Mechanism ◽  
High Tech ◽  
Slight Reduction ◽  
Application Process ◽  
Temperature Oxidation ◽  
Outward Diffusion ◽  
Resistance Performance

High temperature lubricating composites have been widely used in aerospace and other high-tech industries. In the actual application process, high temperature oxidation resistance is a very importance parameter. In this paper, BaO/TiO2-enhanced NiAl-based composites were prepared by vacuum hot-press sintering. The oxidation resistance performance of the composites at 800 °C was investigated. The composites exhibited very good sintered compactness and only a few pores were present. Meanwhile, the composite had excellent oxidation resistance properties due to the formation of a dense Al2O3 layer which could prevent further oxidation of the internal substrate; its oxidation mechanism was mainly decided by the outward diffusion of Al and the inward diffusion of O. The addition of BaO/TiO2 introduced more boundaries and made the Kp value increase from 1.2 × 10−14 g2/cm4 s to 3.3 × 10−14 g2/cm4 s, leading to a slight reduction in the oxidation resistance performance of the composites—although it was still excellent.

scholarly journals High Temperature Oxidation Behavior of New Martensitic Heat-Resistant Steel

2021 ◽  
Author(s):  
Ziming BAO ◽  
Renheng HAN ◽  
Yanqing ZHU ◽  
Hong LI ◽  
Ning LI ◽  
...  
Keyword(s):  
High Temperature ◽  
Oxide Film ◽  
Oxidation Resistance ◽  
High Temperature Oxidation ◽  
Oxidation Behavior ◽  
Oxidation Mechanism ◽  
Resistant Steel ◽  
Temperature Oxidation ◽  
Heat Resistant Steel ◽  
Heat Resistant

The research focuses on the high temperature oxidation resistance of martensitic heat-resistant steel. A new type of martensitic heat-resistant steel was developed with the addition of Al and Cu, and the oxidation behavior of the new martensitic heat-resistant steel at 650 °C and 700 °C was analyzed. The high temperature oxidation kinetics curves of new martensitic heat-resistant steel at 650 °C and 700 °C were determined and plotted by cyclic oxidation experiment and discontinuous weighing method. XRD technique was applied to qualitatively analyze the surface oxide of the material after oxidation. The surface and cross-section morphology of the material were observed by field emission scanning electron microscope (SEM) and energy dispersive spectrometer (EDS), and the oxidation mechanism at high temperature was analyzed. The results show that the oxide film can be divided into two layers after oxidation at 650 ºC for 200 h. The outer oxide film is mainly composed of Fe and Cu oxides, and the inner oxide film is mainly composed of Al2O3, SiO2 and Cr2O3. After oxidation at 700 ºC for 200 h, the outer layer is mainly composed of Fe, Cu, Mn oxides, and the inner layer is mainly composed of Cr, Al and Si oxides. The addition of a small amount of Cu promotes the diffusion of Al and Si elements, facilitates the formation of Al2O3 and SiO2, and improves the high-temperature oxidation resistance of martensitic heat-resistant steel.

State of the Art and Prospects on Laser Clad Multiphase Transition Metal Silicides Wear and Corrosion Resistant Coatings for the Aerospace and Petrochemical Industries

2006 ◽  
Vol 118 ◽  
pp. 235-242 ◽  
Author(s):  
H.M. Wang ◽  
L.X. Cai
Keyword(s):  
High Temperature ◽  
Transition Metal ◽  
Oxidation Resistance ◽  
Fretting Wear ◽  
Temperature Oxidation ◽  
Corrosion Resistant ◽  
Good Oxidation Resistance ◽  
Test Conditions ◽  
Metal Silicides ◽  
Wear And Corrosion

Wear and corrosion resistant multi-phase transition metal silicides coatings including W2Ni3Si/W5Si3, Ti5Si3/NiTi2, Ti2Ni3Si/NiTi, etc, were developed and fabricated by laser cladding process. Tribological properties were evaluated under dry sliding and reciprocating fretting wear test conditions and the responding wear mechanisms were discussed as functions of microstructure constitutions and test conditions. High temperature oxidation resistance of the coatings was investigated. The coatings exhibited excellent combination of room and high temperature metallic sliding wear resistance, fretting propertiy, metallic tribological compatibility, good oxidation resistance and abnormal wear-load dependence. Applications of the coatings were prospected for the aerospace, petrochemical and energy-processing industries.

scholarly journals Study on the Pre-Oxidation and Resulting Oxidation Mechanism and Kinetics of Mo-9Si-8B Alloy

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5309
Author(s):  
Cheng Wang ◽  
Qiuliang Li ◽  
Zhenping Guo ◽  
Xiangrong Li ◽  
Xiangyu Ding ◽  
...  
Keyword(s):  
High Temperature ◽  
Oxidation Resistance ◽  
High Temperature Oxidation ◽  
Cyclic Oxidation ◽  
Initial Period ◽  
Oxidation Mechanism ◽  
Protective Layer ◽  
Temperature Oxidation ◽  
Locking Mechanism ◽  
Kinetics Of

Molybdenum silicon boron alloy is regarded as the next generation of superalloy that is expected to replace nickel-based superalloys. However, the high-temperature oxidation resistance of Mo-Si-B alloy has always been an issue worth studying. In this study, Mo-9Si-8B alloy was prepared via a plasma oscillatory pressure sintering process and pre-oxidized at 1300 °C while maintaining a certain balance of mechanical and oxidation properties. The influence of the oxide protective layer on its performance at high temperature of 1150 °C was explored, the micro-mechanism of its performance and its failure mode of the hinge-locking mechanism was illustrated, and finally, its oxidation kinetics was inferred. In conclusion, pre-oxidized Mo-9Si-8B (at.%) alloy did play a role in delaying the oxidation process during the initial period of cyclic oxidation. However, with the increase of cyclic oxidation time, the improvement of high-temperature oxidation resistance was limited.

Sign in / Sign up

Export Citation Format

Share Document