Oxidation Behaviors of Two and Three Phase Mo-Si-B Alloys via Si Pack Cementation

2012 ◽  
Vol 706-709 ◽  
pp. 2446-2449
Author(s):  
Young Ho Song ◽  
Joon Sik Park ◽  
Jeong Min Kim ◽  
Seong Hoon Yi
Keyword(s):  
High Temperature ◽  
Oxidation Resistance ◽  
Alloy System ◽  
Underlying Mechanism ◽  
High Temperature Strength ◽  
Three Phase ◽  
Phase Combination ◽  
Temperature Exposure ◽  
Poor Oxidation Resistance ◽  
Oxidation Behaviors

Mo-Si-B alloys have been received an attention due to the high temperature strength and phase stability. However, the nature of poor oxidation resistance often limits the application of the alloy system. In order to resolve the poor oxidation resistance of the alloy system, in this study, the oxidation behaviors of Si diffusion coated Mo-Si-B alloys have been investigated in order to identify the underlying mechanism for the effect of the constituent of the phase combination of Mo-Si-B alloys. The oxidation tests performed at 1100 °C show that the produced MoSi2 phase, as a result of the coatings, give an excellent oxidation resistance at prolonged high temperature exposure in air. The oxidation behaviors of uncoated and Si coated Mo-Si-B alloys have been discussed in terms of microstructural observations during oxidation tests.

Oxidation Behaviors of Pure Ti Thermal Plasma Spray Coated Mo-Si-B Alloys

2011 ◽  
Vol 695 ◽  
pp. 365-368 ◽  
Author(s):  
Young Ho Song ◽  
Joon Sik Park ◽  
Jeong Min Kim ◽  
Seong Hoon Yi
Keyword(s):  
High Temperature ◽  
Oxidation Resistance ◽  
Alloy System ◽  
Underlying Mechanism ◽  
High Temperature Strength ◽  
Air Atmosphere ◽  
Elemental Component ◽  
Ti Powder ◽  
Poor Oxidation Resistance ◽  
Oxidation Behaviors

Mo-Si-B alloys have been received an attention due to the high temperature strength and phase stability. However, the nature of poor oxidation resistance often limits the application of the alloy system. The unstable MoO3 phase is naturally produced when the alloys were exposed at low and /or high temperature in an air atmosphere. In order to resolve the poor oxidation resistance of the alloy system, several attempts have been made via surface coatings and/or component additions. In this study, the oxidation behaviors of the Ti powder thermal spray coated Mo-Si-B alloys have been investigated in order to identify the underlying mechanism for the effect of precursor Ti coatings on Mo-Si-B alloys. The oxidation tests performed at 1100 °C show that the Ti powder was tightly bonded and reacted with the surface of the substrate, and TiO2 layer was formed at the outer surface of the coated Ti layer as a result of oxidation exposure. The oxidation behaviors of pure elemental component coated Mo-Si-B alloys have been discussed in terms of microstructural observations during oxidation tests.

Phase transformation and layer evolution in molybdenum disilicide-silicon carbide nanolayered coatings

1994 ◽  
Vol 52 ◽  
pp. 538-539
Author(s):  
H. Kung ◽  
T. R. Jervis ◽  
J.-P. Hirvonen ◽  
M. Nastasi ◽  
T. E. Mitchell ◽  
...  
Keyword(s):  
Phase Transformation ◽  
High Temperature ◽  
Oxidation Resistance ◽  
Elevated Temperatures ◽  
Matrix Material ◽  
Molybdenum Disilicide ◽  
High Temperature Strength ◽  
Cross Sectional ◽  
Good Oxidation Resistance ◽  
Structural Applications

MoSi2 is a potential matrix material for high temperature structural composites due to its high melting temperature and good oxidation resistance at elevated temperatures. The two major drawbacksfor structural applications are inadequate high temperature strength and poor low temperature ductility. The search for appropriate composite additions has been the focus of extensive investigations in recent years. The addition of SiC in a nanolayered configuration was shown to exhibit superior oxidation resistance and significant hardness increase through annealing at 500°C. One potential application of MoSi2- SiC multilayers is for high temperature coatings, where structural stability ofthe layering is of major concern. In this study, we have systematically investigated both the evolution of phases and the stability of layers by varying the heat treating conditions.Alternating layers of MoSi2 and SiC were synthesized by DC-magnetron and rf-diode sputtering respectively. Cross-sectional transmission electron microscopy (XTEM) was used to examine three distinct reactions in the specimens when exposed to different annealing conditions: crystallization and phase transformation of MoSi2, crystallization of SiC, and spheroidization of the layer structures.

HASTELLOY ALLOY X

Alloy Digest ◽  
1954 ◽  
Vol 3 (12) ◽  
Keyword(s):  
High Temperature ◽  
Physical Properties ◽  
Tensile Properties ◽  
Oxidation Resistance ◽  
High Temperatures ◽  
Heat Treating ◽  
Operating Conditions ◽  
Molybdenum Alloy ◽  
High Temperature Strength ◽  
Nickel Chromium

Abstract HASTELLOY Alloy X is a nickel-chromium-iron-molybdenum alloy recommended for high-temperature applications. It has outstanding oxidation resistance at high temperatures under most operating conditions, and good high-temperature strength. This datasheet provides information on composition, physical properties, and tensile properties as well as creep. It also includes information on forming, heat treating, and machining. Filing Code: Ni-14. Producer or source: Haynes Stellite Company.

AK STEEL 441

Alloy Digest ◽  
2006 ◽  
Vol 55 (6) ◽  
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Tensile Properties ◽  
Oxidation Resistance ◽  
Ferritic Stainless Steel ◽  
High Temperature Oxidation ◽  
High Temperature Strength ◽  
Temperature Oxidation ◽  
Temperature Performance

Abstract AK Steel 441 has good high-temperature strength, an equiaxed microstructure, and good high-temperature oxidation resistance. The alloy is a niobium-bearing ferritic stainless steel. This datasheet provides information on composition, hardness, and tensile properties as well as deformation. It also includes information on high temperature performance and corrosion resistance as well as forming and joining. Filing Code: SS-965. Producer or source: AK Steel.

KUBOTA HK40 and HK50

Alloy Digest ◽  
2007 ◽  
Vol 56 (10) ◽  
Keyword(s):  
High Temperature ◽  
Physical Properties ◽  
Carbon Content ◽  
Tensile Properties ◽  
Oxidation Resistance ◽  
Heat Treating ◽  
Industrial Applications ◽  
High Temperature Strength ◽  
Ni Alloys ◽  
Moderately High Temperature

Abstract Kubota alloys HK40 and HK50 are austenitic Fe-Cr-Ni alloys that have been standard heat-resistant materials for more than four decades. With moderately high temperature strength, oxidation resistance, and carburization resistance the alloys are used in a wide variety of industrial applications. HK 50 has slightly higher carbon content. This datasheet provides information on composition, physical properties, and tensile properties as well as creep. It also includes information on casting, heat treating, machining, and joining. Filing Code: SS-998. Producer or source: Kubota Metal Corporation, Fahramet Division.

Permodur 4742

Alloy Digest ◽  
2018 ◽  
Vol 67 (4) ◽  
Keyword(s):  
High Temperature ◽  
Physical Properties ◽  
Tensile Properties ◽  
Oxidation Resistance ◽  
Heat Treating ◽  
High Temperature Strength ◽  
Aluminum Addition

Abstract Permodur 4742 is an alloy with good high temperature strength and oxidation resistance and has an aluminum addition. The alloy is also called Ferrotherm 4742 at Edelstahlwerke Südwestfalen GmbH. This datasheet provides information on composition, physical properties, hardness, and tensile properties. It also includes information on forming, heat treating, machining, and joining. Filing Code: SS-1284. Producer or source: Deutsche Edelstahlwerke.

scholarly journals Coating Reactions on Vanadium and V-Si-B Alloys during Powder Pack-Cementation

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 4099
Author(s):  
Georg Hasemann ◽  
Chad Harris ◽  
Manja Krüger ◽  
John H. Perepezko
Keyword(s):  
High Temperature ◽  
Oxidation Resistance ◽  
Refractory Metal ◽  
Pack Cementation ◽  
Solid Solution Phase ◽  
Major Drawback ◽  
Three Phase ◽  
Structural Applications ◽  
New Type ◽  
Refractory Metal Alloys

Alloys in the V-Si-B system are a new and promising class of light-weight refractory metal materials for high temperature applications. Presently, the main attention is focused on three-phase alloy compositions that consist of a vanadium solid solution phase and the two intermetallic phases V3Si and V5SiB2. Similar to other refractory metal alloys, a major drawback is the poor oxidation resistance. In this study, initial pack-cementation experiments were performed on commercially available pure vanadium and a three-phase alloy V-9Si-5B to achieve an oxidation protection for this new type of high temperature material. This advance in oxidation resistance now enables the attractive mechanical properties of V-Si-B alloys to be used for high temperature structural applications.

The Investigation of the Interdiffusion Barrier in TiAl/MCrAlY System

2010 ◽  
Vol 654-656 ◽  
pp. 1920-1923 ◽  
Author(s):  
Wen Wang ◽  
Yu Xian Cheng ◽  
Sheng Long Zhu ◽  
Fu Hui Wang ◽  
Li Xin
Keyword(s):  
High Temperature ◽  
Oxidation Resistance ◽  
Diffusion Barrier ◽  
High Temperature Oxidation ◽  
Temperature Oxidation ◽  
The Poor ◽  
Structural Applications ◽  
Nicraly Coating ◽  
Overlay Coatings ◽  
Poor Oxidation Resistance

TiAl based alloys are promising candidates for structural applications at high temperature. However, the poor oxidation resistance above 800oC obviously restrains their applications. Although NiCrAlY overlay coatings can remarkably improve the high temperature oxidation resistance of TiAl, serious inward diffusion of Ni from the coating to the substrate occurs which could reduce the lifetime of the coating/substrate system. Apparently, the development of interdiffusion barrier could overcome the disadvantage of the NiCrAlY/TiAl system. In this work, Ta, TiN and Cr2O3 interlayers were deposited between NiCrAlY coating and γ-TiAl substrate as diffusion barrier (DB). The interdiffusion behavior of the TiAl/DB/NiCrAlY system was investigated at 1000°C. The results showed that the metallic and nitride interlayers cannot retard the interdiffusion of Ni effectively. As an active diffusion barrier, the oxide interlayer obviously suppressed the inward diffusion of Ni from the coating to the substrate by the formation of alumina-rich layers at both the TiAl/DB and DB/NiCrAlY interfaces.

Microstructure and Deformation of Ti-22Al-23Nb Orthorhombic-Based Monolithic and Composite Titanium Aluminides

1994 ◽  
Vol 350 ◽  
Author(s):  
François-charles dary ◽  
Shiela R. Woodard ◽  
Tresa M. Pollock
Keyword(s):  
High Temperature ◽  
Titanium Aluminides ◽  
Matrix Composites ◽  
Low Oxygen ◽  
Microstructural Stability ◽  
Two Phase ◽  
Intermetallic Matrix ◽  
Three Phase ◽  
Intermetallic Matrix Composites ◽  
Temperature Exposure

AbstractA new class of intermetallic matrix composites (IMC's) based on orthorhombic titanium aluminides offer attractive properties for high-temperature structural components at temperatures up to 760°C. Results from an ongoing study on the microstructural stability and mechanical properties of the orthorhombic-based alloy Ti-22Al–23Nb (at%), in both monolithic and composite forms, are discussed. Oxygen acquired during processing or as a result of high-temperature exposure in air or vacuum has a pronounced influence on the microstructure of the monolithic and composite materials. Two-phase lath microstructures of ordered beta (βo) + orthorhombic (O) phases produced by processing low oxygen material above the beta transus are morphologically stable at 760°C. Conversely, in higher-oxygen three-phase microstructures containing O+βo+ α2(Ti3Al), lath coarsening and additional precipitation of α2 in oxygen-enriched sheet surface regions is observed. At 760°C/69MPa the two-phase lath microstructure has a higher creep resistance and lower tensile strength compared to the three-phase α2- containing microstructures of the higher oxygen material.

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