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.

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 Irradiation Behaviors in BCC Multi-Component Alloys with Different Lattice Distortions

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 706
Author(s):  
Yue Su ◽  
Songqin Xia ◽  
Jia Huang ◽  
Qingyuan Liu ◽  
Haocheng Liu ◽  
...  
Keyword(s):  
Single Phase ◽  
Vacuum Arc ◽  
Face Centered Cubic ◽  
Body Centered Cubic ◽  
Chemical Complexity ◽  
Arc Melting ◽  
Vacuum Arc Melting ◽  
Lattice Distortions ◽  
Face Centered ◽  
Displacement Per Atom

Recently, the irradiation behaviors of multi-component alloys have stimulated an increasing interest due to their ability to suppress the growth of irradiation defects, though the mostly studied alloys are limited to face centered cubic (fcc) structured multi-component alloys. In this work, two single-phase body centered cubic (bcc) structured multi-component alloys (CrFeV, AlCrFeV) with different lattice distortions were prepared by vacuum arc melting, and the reference of α-Fe was also prepared. After 6 MeV Au ions irradiation to over 100 dpa (displacement per atom) at 500 °C, the bcc structured CrFeV and AlCrFeV exhibited significantly improved irradiation swelling resistance compared to α-Fe, especially AlCrFeV. The AlCrFeV alloy possesses superior swelling resistance, showing no voids compared to α-Fe and CrFeV alloy, and scarce irradiation softening appears in AlCrFeV. Owing to their chemical complexity, it is believed that the multi-component alloys under irradiation have more defect recombination and less damage accumulation. Accordingly, we discuss the origin of irradiation resistance and the Al effect in the studied bcc structured multi-component alloys.

scholarly journals Study on Microstructure and In Situ Tensile Deformation Behavior of Fe-25Mn-xAl-8Ni-C Alloy Prepared by Vacuum Arc Melting

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 814
Author(s):  
Yaping Bai ◽  
Meng Li ◽  
Chao Cheng ◽  
Jianping Li ◽  
Yongchun Guo ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Deformation Behavior ◽  
Tensile Deformation ◽  
Austenite Phase ◽  
Vacuum Arc ◽  
Al Content ◽  
Arc Melting ◽  
Vacuum Arc Melting ◽  
Tensile Deformation Behavior

In this study, Fe-25Mn-xAl-8Ni-C alloys (x = 10 wt.%, 11 wt.%, 12 wt.%, 13 wt.%) were prepared by a vacuum arc melting method, and the microstructure of this series of alloys and the in situ tensile deformation behavior were studied. The results showed that Fe-25Mn-xAl-8Ni-C alloys mainly contained austenite phase with a small amount of NiAl compound. With the content of Al increasing, the amount of austenite decreased while the amount of NiAl compound increased. When the Al content increased to 12 wt.%, the interface between austenite and NiAl compound and austenitic internal started to precipitate k-carbide phase. In situ tensile results also showed that as the content of Al increased, the alloy elongation decreased gradually, and the tensile strength first increased and then decreased. When the Al content was up to 11 wt.%, the elongation and tensile strength were 2.6% and 702.5 MPa, respectively; the results of in situ tensile dynamic observations show that during the process of stretching, austenite deformed first, and crack initiation mainly occurred at the interface between austenite and NiAl compound, and propagated along the interface, resulting in fracture of the alloy.

Oxidation Behaviour of Nickel-Based Alloys Containing High Re Contents Comparable to the Third Generation Nickel-Based Superalloys

2004 ◽  
Vol 449-452 ◽  
pp. 349-352 ◽  
Author(s):  
Yoshinori Murata ◽  
Masahiko Morinaga ◽  
Ryokichi Hashizume
Keyword(s):  
High Temperature ◽  
Oxidation Resistance ◽  
High Temperature Oxidation ◽  
Oxidation Behaviour ◽  
The Other ◽  
Third Generation ◽  
Temperature Oxidation ◽  
Oxidation Test ◽  
Al Content ◽  
The Third

In order to elucidate the Re effect on oxidation resistance, a high-temperature oxidation test was conducted with two groups of Ni-based superalloys. One group of alloys was characterized by 10mol%Al content (10-Al series). The other group of alloys was characterized by 15mol%Al content (15-Al series). The oxidation resistance decreased clearly with increasing Re content in the 10-Al series alloys, but did not in the 15-Al series alloys.

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.

Effect of Mo and Ni Content on the Mechanical Properties of Low Carbon and Alloy Steel Casting Sample for Coal-Mining Machinery

2012 ◽  
Vol 476-478 ◽  
pp. 329-333
Author(s):  
Zhi Ying Ma ◽  
Yi Tao Yang
Keyword(s):  
Mechanical Properties ◽  
Melting Furnace ◽  
Vacuum Arc ◽  
Low Carbon ◽  
Alloy Casting ◽  
Arc Melting ◽  
Vacuum Arc Melting ◽  
Ni Content ◽  
Mining Machinery ◽  
Casting Steel

The effect of Mo and Ni content on the mechanical properties of low carbon and alloy casting steel by using Vacuum Arc Melting Furnace had been studied in this paper. The results indicated that increasing Mo or Ni content would enhance the hardness and strength of the steel separately, with some of elongation loss. It showed that ferrite refined with the increasing alloy content. The combinations of Mo and Ni content were of importance for comprehensive mechanical properties and wear resistance. The appropriate content in low carbon casting steel with 0.02%Nb was 0.5%-0.6%Mo and 0.2%-0.4%Ni.

Ti5Si3/β-Ti nano-core–shell structure toughened glassy Ti alloy matrix biocomposites

RSC Advances ◽  
2015 ◽  
Vol 5 (11) ◽  
pp. 8355-8361 ◽  
Author(s):  
Chunxiang Cui ◽  
Ling Bai ◽  
Shuangjin Liu ◽  
Yumin Qi ◽  
Lichen Zhao
Keyword(s):  
Shell Structure ◽  
Melting Furnace ◽  
Vacuum Arc ◽  
Core Shell ◽  
Ti Alloy ◽  
Alloy Matrix ◽  
Arc Melting ◽  
Vacuum Arc Melting ◽  
Core Shell Structure

In the experiment, Ti75Zr11Si9Fe5 and Ti66Zr11Si15Fe5Mo3 ingots were prepared by vacuum arc-melting furnace.

Comparison of Different Fluorine-treatments for Improved High Temperature Oxidation Resistance of TiAl-alloys

2011 ◽  
Vol 1295 ◽  
Author(s):  
A. Donchev ◽  
M. Schütze ◽  
A. Kolitsch ◽  
R. Yankov
Keyword(s):  
High Temperature ◽  
Oxidation Resistance ◽  
Elevated Temperatures ◽  
Fluorine Content ◽  
Intermediate Formation ◽  
Experimental Investigations ◽  
Alumina Layer ◽  
Temperature Oxidation ◽  
Tial Alloys ◽  
Al Content

ABSTRACTIntermetallic TiAl-alloys can replace the heavier Ni-based superalloys in several high temperature applications with regards to their mechanical properties, however they can not be used at temperatures above 800°C in oxidizing environments for longer times because of insufficient oxidation resistance. Despite an Al-content of about 45 at.% in technical alloys, no protective alumina layer is formed because the thermodynamic stabilities of titanium oxide and aluminum oxide are of the same order of magnitude. Therefore a mixed TiO2/Al2O3-scale is formed which is fast growing so that the metal consumption rate is quite high. On the other hand the formation of a slow growing alumina layer is promoted by a fluorine treatment. This so called fluorine effect leads to the preferential intermediate formation of gaseous aluminum fluorides at elevated temperatures if the fluorine content at the surface stays within a defined concentration range. These fluorides are converted into solid Al2O3 due to the high oxygen partial pressure of the high temperature service environment forming a protective pure Al2O3 surface scale. In this paper results of high temperature oxidations tests of several technical TiAl-alloys will be presented. Different F-treatments e.g. dipping or spaying which are easy to apply have been used and their results will be compared. The mass change data of the F-treated specimens are always lower than those of the untreated ones. Post experimental investigations such as light microscopy, scanning electron microscopy and energy dispersive X-ray analysis reveal the formation of a thin alumina layer on the F-treated samples after optimization of the process while a thick mixed scale is found on the untreated samples. The results will be discussed in view of an optimized procedure and the future use of TiAl-components in high temperature environments.

Fabrication and Properties of TiB2 Reinforced Cu Composites by Electromagnetic Stirring

2004 ◽  
Vol 449-452 ◽  
pp. 297-300 ◽  
Author(s):  
Taek Kyun Jung ◽  
Sung Chul Lim ◽  
Hyouk Chon Kwon ◽  
Mok Soon Kim
Keyword(s):  
Annealing Temperature ◽  
Volume Fraction ◽  
Melting Furnace ◽  
Electromagnetic Stirring ◽  
Vacuum Arc ◽  
Arc Melting ◽  
Vacuum Arc Melting ◽  
Copper Melt ◽  
Mean Size ◽  
The Mean

Cu-Ti and Cu-B alloys were separately cast in vacuum arc melting furnace for alloying. These alloys were added to the copper melt of 1500K in the induction furnace and performed electromagnetic stirring at 1000rpm. The cast ingot(dia : 70mm, length : 100mm) was hot extruded with the extrusion ratio of 13:1 after heating at 1073K for 1 hour. The TiB 2 precipitates were observed in the extruded materials and the mean size of TiB 2 precipitates was found to be about 1.5µm. The volume fraction of TiB 2 varies due to the density difference between the TiB2 and the copper melt. With the increasing of TiB2 contents from 3 to 8 vol.%, the hardness and the tensile strength increased from 951 to 140Hv and from 248 to 278MPa, respectively, and the electrical conductivity decreased from 82 to 70%IACS. However, the mean size of TiB 2 particle was not increased despite increasing an annealing temperature.

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