scholarly journals Fracture Strength at Ambient Temperature and High Temperature Self-healing Capability of Titanium Aluminide Coatings Produced by IR Laser Fusion Reaction

1993 ◽  
Vol 42 (12) ◽  
pp. 790-796
Author(s):  
Masanobu Shinya ◽  
Hisaaki Yasumuro ◽  
Mikio Takemoto
Keyword(s):  
High Temperature ◽  
Ambient Temperature ◽  
Fracture Strength ◽  
Titanium Aluminide ◽  
Fusion Reaction ◽  
Laser Fusion ◽  
Self Healing ◽  
Aluminide Coatings ◽  
Ir Laser

Glasses and Multi-Component Sol-Gels for Use as High-Temperature Protective Coatings

1990 ◽  
Vol 180 ◽  
Author(s):  
Lauri J. Devore ◽  
Nora R. Osborne
Keyword(s):  
Thin Film ◽  
High Temperature ◽  
Ambient Temperature ◽  
Titanium Aluminide ◽  
Protective Coatings ◽  
Sol Gel ◽  
Film Coatings ◽  
Interfacial Conditions ◽  
Thin Film Coatings

ABSTRACTTwo multi-component sol-gel compositions were developed and compared to several commercially available high-temperature glasses. All were then used and characterized as protective coatings for intermetallic titanium aluminide.The sol-gels were studied as thin film coatings and the commercial glasses were studied as enameled coatings. Attention was given to (1) the effect of the application temperature on the original microstructure of the metal, and (2) the role of interfacial conditions between the glass and metal in cyclic and isothermal thermal cycles between ambient temperature and 760°C (1400°F).

Microstructural characterization of plasma-processed Ti-Al metal matrix composites

1989 ◽  
Vol 47 ◽  
pp. 552-553
Author(s):  
M. G. Burke ◽  
M. N. Gungor ◽  
M. A. Burke
Keyword(s):  
High Temperature ◽  
Titanium Aluminide ◽  
Plasma Processing ◽  
Microstructural Characterization ◽  
High Temperature Strength ◽  
Matrix Composites ◽  
Intermetallic Matrix ◽  
Long Time ◽  
Strength And Stiffness ◽  
Intermetallic Matrix Composites

Intermetallic matrix composites are candidates for ultrahigh temperature service when light weight and high temperature strength and stiffness are required. Recent efforts to produce intermetallic matrix composites have focused on the titanium aluminide (TiAl) system with various ceramic reinforcements. In order to optimize the composition and processing of these composites it is necessary to evaluate the range of structures that can be produced in these materials and to identify the characteristics of the optimum structures. Normally, TiAl materials are difficult to process and, thus, examination of a suitable range of structures would not be feasible. However, plasma processing offers a novel method for producing composites from difficult to process component materials. By melting one or more of the component materials in a plasma and controlling deposition onto a cooled substrate, a range of structures can be produced and the method is highly suited to examining experimental composite systems. Moreover, because plasma processing involves rapid melting and very rapid cooling can be induced in the deposited composite, it is expected that processing method can avoid some of the problems, such as interfacial degradation, that are associated with the relatively long time, high temperature exposures that are induced by conventional processing methods.

scholarly journals Polar poly(n-butyl acrylate)-g-polyacrylonitrile elastomer with high temperature elasticity and healability as flexible electronic substrate

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Yuzhu Zheng ◽  
Deli Xu ◽  
Shiyou Tian ◽  
Manli Li ◽  
Wenwen Wang ◽  
...  
Keyword(s):  
High Temperature ◽  
Graft Copolymer ◽  
Butyl Acrylate ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Self Healing ◽  
Chemical Structures ◽  
Flexible Electronic ◽  
Ag Nanowires ◽  
Cyano Groups

AbstractIn this work, graft copolymer poly (n-butyl acrylate)-g-polyacrylonitrile with poly (n-butyl acrylate) as backbones and polyacrylonitrile as side chains (PnBA-g-PAN) was synthesized by macromonomer method and emulsion polymerization. The macromonomer was synthesized by atom transfer radical polymerization and end-group modification. The chemical structures and thermal properties of macromonomer and graft copolymer were investigated by FTIR, GPC, NMR and TGA, etc. The mechanical properties of graft copolymer elastomer was also measured by uniaxial tensile test. Rheological properties at different temperature and mechanical property demonstrated that graft copolymer elastomer possessed elasticity until 180 oC because of cyclization of cyano groups. Ag nanowires@PnBA-g-PAN composite elastomer was developed, and the resulted material exhibited autonomic healing property on account of segments’ flexibility and dynamic interaction between Ag nanowires (AgNWs) and cyano groups. This is a general method for generation of elastomer with high temperature elasticity and fast self-healing. The composite elastomer has potential application in flexible electronic conductor.

Analysis of the Ventilation Effects on Radon-222 Exhalation in a Dead-End Tunnel

2015 ◽  
Vol 713-715 ◽  
pp. 304-313
Author(s):  
Shu Guang Wang ◽  
Wei Yang ◽  
Qing Chen ◽  
Jian Hua Chen ◽  
Cong Han
Keyword(s):  
High Temperature ◽  
Ambient Temperature ◽  
Natural Ventilation ◽  
Weather Conditions ◽  
Calculation Model ◽  
Radon Exhalation Rate ◽  
Exhalation Rate ◽  
Radon Exhalation ◽  
Exhaust Ventilation ◽  
Dead End

The regularity of radon exhalation rate in the over-broken granite tunnel is susceptible to weather conditions and ventilation styles. Based on the calculation model of radon exhalation in tunnel, some experiments have been carried out to analyze the variations of radon exhalation in cases of natural ventilation, blowing ventilation and exhaust ventilation separately. The results show that there is a linear relation between the radon exhalation and the natural ventilation quantity, and also between the radon exhalation and the ambient temperature; the radon exhalation in the case of exhaust ventilation is 63% higher than that in the blowing case under the condition of the same ventilation quantity and ambient temperature. Therefore, it is suggested that operation in the tunnel in high temperature be avoided in summer, and the blowing ventilation be adopted as an effective way for ventilation.

Recent Advances in Development and Processing of Titanium Aluminide Alloys

2000 ◽  
Vol 646 ◽  
Author(s):  
Fritz Appel ◽  
Helmut Clemens ◽  
Michael Oehring
Keyword(s):  
High Temperature ◽  
Titanium Aluminide ◽  
Titanium Aluminides ◽  
Environmental Stability ◽  
Physical Metallurgy ◽  
Specific Strength ◽  
Wide Range ◽  
Structural Applications ◽  
Strength And Stiffness ◽  
Nickel Base

ABSTRACTIntermetallic titanium aluminides are one of the few classes of emerging materials that have the potential to be used in demanding high-temperature structural applications whenever specific strength and stiffness are of major concern. However, in order to effectively replace the heavier nickel-base superalloys currently in use, titanium aluminides must combine a wide range of mechanical property capabilities. Advanced alloy designs are tailored for strength, toughness, creep resistance, and environmental stability. Some of these concerns are addressed in the present paper through specific comments on the physical metallurgy and technology of gamma TiAl-base alloys. Particular emphasis is placed on recent developments of TiAl alloys with enhanced high-temperature capability.

Self-healing behavior of Cr-coated Zr alloy cladding in high temperature steam oxidation process

2022 ◽  
Vol 558 ◽  
pp. 153327
Author(s):  
Hai-Bin Ma ◽  
Ya-Huan Zhao ◽  
Yang Liu ◽  
Jing-Ting Zhu ◽  
Jun Yan ◽  
...  
Keyword(s):  
High Temperature ◽  
Oxidation Process ◽  
Steam Oxidation ◽  
Self Healing ◽  
High Temperature Steam ◽  
Zr Alloy

Localized Oxidation Near Cracks and Lamellar Boundaries in a Gamma Titanium Aluminide Alloy

1994 ◽  
Vol 364 ◽  
Author(s):  
J. Kameda ◽  
C. R. Gold ◽  
E. S. Lee ◽  
T. E. Bloomer ◽  
M. Yamaguchi
Keyword(s):  
High Temperature ◽  
Titanium Aluminide ◽  
Lamellar Structure ◽  
Oxidation Behavior ◽  
Stress Axis ◽  
Surface Cracks ◽  
Gamma Titanium Aluminide ◽  
Titanium Aluminide Alloy ◽  
Scanning Auger Microprobe ◽  
Local Oxidation

AbstractSmall punch (SP) tests on single grained titanium aluminide (Ti-48 at.%Al) specimens with 12° and 80° lamellar orientations with respect to the tensile stress axis were conducted at 1123 K in air. Brittle cracks readily extended through the thickness in the 80° lamellar structure. In a SP specimen with the 12° lamellar structure load-interrupted at the strain of 0.43%, surface cracks with the depth of 15–25 μm were formed along lamellar boundaries. Local oxidation behavior on partly sputtered surfaces in the load-interrupted 12° lamellar specimen was examined using scanning Auger microprobe (SAM). Oxygen enriched regions were observed near cracks and some lamellar layers. The mechanisms of high temperature oxygen-induced cracking are discussed in terms of the local oxidation near cracks and lamellar boundaries.

High-Temperature Erosion Resistance of Coatings for Gas Turbine

1992 ◽  
Vol 114 (2) ◽  
pp. 242-249 ◽  
Author(s):  
W. Tabakoff ◽  
A. Hamed ◽  
M. Metwally ◽  
M. Pasin
Keyword(s):  
High Temperature ◽  
Protective Coatings ◽  
Coal Ash ◽  
Mass Effect ◽  
Impact Angle ◽  
Unit Weight ◽  
Weight Losses ◽  
Aluminide Coatings ◽  
Particle Flows ◽  
The Impact

An experimental investigation was conducted to study the ash particle rebound characteristics and the associated erosion behavior of superalloys and aluminide coatings subjected to gas-particle flows at elevated temperature. A three-component LDV system was used to measure the restitution parameters of 15 micron mean diameter coal-ash particles impacting some widely used superalloys and coatings at different angles. The presented results show the variation of the particle restitution ratios with the impingement angle for the coated and uncoated superalloys. The erosion behaviors of INCO-738, MAR 246 and X40 superalloys and protective coatings C, N, RT22 and RT22B also have been investigated experimentally at high temperature using a specially designed erosion tunnel. The erosion results show the effect of velocity, temperature and the impact angle on the erosion rate (weight loss per unit weight of particles). Based on the experimental results of the particle mass effect on both weight losses and erosion rates, the coating lives have been estimated for different particle concentrations.

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