Enhancing Performance of Silicon-Modified Slurry Aluminides on Turbine Components Operating in Marine Environments

1995 ◽  
Author(s):  
David Berry ◽  
Mehar Chand Meelu ◽  
Bruce G. McMordie ◽  
Thomas A. Kircher
Keyword(s):  
High Temperature ◽  
Laboratory Tests ◽  
Elevated Temperatures ◽  
Environmental Contaminants ◽  
Alumina Scale ◽  
Cobalt Alloys ◽  
Combined Effects ◽  
Marine Environments ◽  
Critical Elements ◽  
High Concentrations

A variety of coatings have been designed to protect turbine components from corrosion due to the combined effects of environmental contaminants, fuel impurities and elevated temperatures. The most effective of these systems rely upon formation of a protective alumina scale to act as a barrier between the gas path environment and the component. Protection offered by these alumina-forming high temperature coatings is increased by a number of additive elements, including platinum and chromium, but silicon (Si) is found to be especially beneficial in coatings exposed to high concentrations of sulfur in marine environments. Silicon-modified slurry aluminides are shown to resist to both high temperature and low temperature hot corrosion on both nickel and cobalt alloys in marine service. Laboratory tests show this corrosion resistance can be further enhanced by redistributing critical elements (particularly silicon) within the microstructure of the silicon-modified aluminide. The benefits of these changes are demonstrated in field engine trials.

Economic Surface Treatment of Ti-Alloys to Improve their Resistance against Environmental High Temperature Attack

2013 ◽  
Vol 551 ◽  
pp. 109-113 ◽  
Author(s):  
Alexander Donchev ◽  
Michael Schütze ◽  
Andreas Kolitsch ◽  
Rossen Yankov
Keyword(s):  
High Temperature ◽  
Surface Treatment ◽  
Oxidation Resistance ◽  
Elevated Temperatures ◽  
Surface Region ◽  
Alumina Scale ◽  
Ti Alloys ◽  
Temperature Capability ◽  
Temperature Exposure ◽  
Al Treatment

High temperature Ti-alloys are usually sophisticated and hence expensive. To allow the use of cheaper alloys at elevated temperatures an economic and easy to apply procedure was developed to improve their high temperature capability. The treatment consists of a combination of Al-enrichment in a shallow surface region plus additional fluorination. The Al-enrichment at elevated temperatures leads to the formation of intermetallic TiAl-phases. These phases improve the oxidation resistance of Ti-alloys but not to a sufficient extent. An additional fluorine treatment of the Al-enriched surface leads to the formation of a protective alumina scale due to the fluorine effect. In this paper results from high temperature exposure tests performed on different Ti-alloys without any treatment and with a combination of Al-treatment plus fluorination are presented. The results are discussed in the view of the use of the optimized Ti-components for several high temperature applications.

High-Temperature Instability of A Cr2Nb-Nb(Cr) Microlaminate Composite

1996 ◽  
Vol 54 ◽  
pp. 374-375
Author(s):  
M. Larsen ◽  
R.G. Rowe ◽  
D.W. Skelly
Keyword(s):  
Heat Treatment ◽  
Solid Solution ◽  
High Temperature ◽  
Elevated Temperatures ◽  
Aircraft Engine ◽  
Lattice Parameter ◽  
Microstructural Stability ◽  
Elevated Temperature Strength ◽  
Cross Sectional ◽  
Bcc Structure

Microlaminate composites consisting of alternating layers of a high temperature intermetallic compound for elevated temperature strength and a ductile refractory metal for toughening may have uses in aircraft engine turbines. Microstructural stability at elevated temperatures is a crucial requirement for these composites. A microlaminate composite consisting of alternating layers of Cr2Nb and Nb(Cr) was produced by vapor phase deposition. The stability of the layers at elevated temperatures was investigated by cross-sectional TEM.The as-deposited composite consists of layers of a Nb(Cr) solid solution with a composition in atomic percent of 91% Nb and 9% Cr. It has a bcc structure with highly elongated grains. Alternating with this Nb(Cr) layer is the Cr2Nb layer. However, this layer has deposited as a fine grain Cr(Nb) solid solution with a metastable bcc structure and a lattice parameter about half way between that of pure Nb and pure Cr. The atomic composition of this layer is 60% Cr and 40% Nb. The interface between the layers in the as-deposited condition appears very flat (figure 1). After a two hour, 1200 °C heat treatment, the metastable Cr(Nb) layer transforms to the Cr2Nb phase with the C15 cubic structure. Grain coarsening occurs in the Nb(Cr) layer and the interface between the layers roughen. The roughening of the interface is a prelude to an instability of the interface at higher heat treatment temperatures with perturbations of the Cr2Nb grains penetrating into the Nb(Cr) layer.

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.

WIELAND-K88

Alloy Digest ◽  
2005 ◽  
Vol 54 (12) ◽  
Keyword(s):  
Thermal Conductivity ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Stress Relaxation ◽  
Copper Alloy ◽  
Elevated Temperatures ◽  
Heat Treating ◽  
Relaxation Resistance ◽  
Temperature Performance ◽  
Very High

Abstract Wieland K-88 is a copper alloy with very high electrical and thermal conductivity, good strength, and excellent stress relaxation resistance at elevated temperatures. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: CU-738. Producer or source: Wieland Metals Inc.

DOWMETAL HZ32XA

Alloy Digest ◽  
1956 ◽  
Vol 5 (7) ◽  
Keyword(s):  
High Temperature ◽  
Physical Properties ◽  
Creep Resistance ◽  
Zirconium Alloy ◽  
Elevated Temperatures ◽  
Heat Treating ◽  
High Temperature Creep ◽  
Aged Condition ◽  
Chemical Company ◽  
Temperature Performance

Abstract DOWMETAL HZ32XA is a magnesium-thorium-zinc-zirconium alloy having good high temperature creep resistance, and is recommended for applications at elevated temperatures. It is used in the artificially aged condition (T5). This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as creep. It also includes information on high temperature performance as well as heat treating, machining, and joining. Filing Code: Mg-26. Producer or source: The Dow Chemical Company.

UDIMET 105

Alloy Digest ◽  
1972 ◽  
Vol 21 (7) ◽  
Keyword(s):  
Corrosion Resistance ◽  
High Temperature ◽  
Physical Properties ◽  
Surface Treatment ◽  
Elevated Temperatures ◽  
Base Alloy ◽  
Heat Treating ◽  
Nickel Base Alloy ◽  
Temperature Performance ◽  
Nickel Base

Abstract UDIMET 105 is a nickel-base alloy which was developed for service at elevated temperatures. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as creep. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: Ni-175. Producer or source: Special Metals Corporation.

CARPENTER L-605 ALLOY

Alloy Digest ◽  
1987 ◽  
Vol 36 (8) ◽  
Keyword(s):  
Corrosion Resistance ◽  
High Temperature ◽  
Elevated Temperatures ◽  
Base Alloy ◽  
High Strength ◽  
Heat Treating ◽  
Temperature Performance ◽  
Cobalt Base Alloy ◽  
Cobalt Base ◽  
Oxidation And Corrosion

Abstract CARPENTER L-605 alloy is a nonmagnetic cobalt-base alloy that has good oxidation and corrosion resistance and high strength at elevated temperatures. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as creep and fatigue. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Co-81. Producer or source: Carpenter.

FANSTEEL 85 METAL

Alloy Digest ◽  
1981 ◽  
Vol 30 (6) ◽  
Keyword(s):  
High Temperature ◽  
Physical Properties ◽  
Creep Strength ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Base Alloy ◽  
Heat Treating ◽  
Good Combination ◽  
Bend Strength ◽  
Temperature Performance

Abstract FANSTEEL 85 METAL is a columbium-base alloy characterized by good fabricability at room temperature, good weldability and a good combination of creep strength and oxidation resistance at elevated temperatures. Its applications include missile and rocket components and many other high-temperature parts. This datasheet provides information on composition, physical properties, microstructure, hardness, elasticity, tensile properties, and bend strength as well as creep. It also includes information on low and high temperature performance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: Cb-7. Producer or source: Fansteel Metallurgical Corporation. Originally published December 1963, revised June 1981.

INCONEL ALLOY N06230

Alloy Digest ◽  
2009 ◽  
Vol 58 (3) ◽  
Keyword(s):  
Fracture Toughness ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Physical Properties ◽  
Tensile Properties ◽  
Elevated Temperatures ◽  
Heat Treating ◽  
Inconel Alloy ◽  
Temperature Performance ◽  
Resistance To Oxidation

Abstract Inconel Alloy N06230 is a Ni-Cr-W alloy with excellent strength and resistance to oxidation at elevated temperatures. This alloy offers good metallurgical stability and is readily fabricated by conventional processes and procedures. This datasheet provides information on composition, physical properties, microstructure, elasticity, and tensile properties as well as fracture toughness. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Ni-667. Producer or source: Special Metals Corporation.

ELEKTRON QH21A

Alloy Digest ◽  
1979 ◽  
Vol 28 (1) ◽  
Keyword(s):  
Fracture Toughness ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Physical Properties ◽  
Surface Treatment ◽  
Elevated Temperatures ◽  
Heat Treating ◽  
Casting Alloy ◽  
Casting Alloys ◽  
Temperature Performance

Abstract ELEKTRON QH21A is a magnesium-base casting alloy developed to meet the ever increasing requirements for casting alloys to operate at elevated temperatures. It is of particular interest to designers and stress engineers for highly stressed components operating at temperatures up to 480 F (250 C), especially where pressure tightness is a requirement. This datasheet provides information on composition, physical properties, and tensile properties as well as fracture toughness, creep, and fatigue. It also includes information on high temperature performance and corrosion resistance as well as casting, heat treating, machining, joining, and surface treatment. Filing Code: Mg-72. Producer or source: Magnesium Elektron Inc..

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