Elevated Temperature Tensile Behavior of Nextel™ 720 Fibers

Materials ◽  
2003 ◽  
Author(s):  
D. M. Pai ◽  
S. N. Yarmolenko ◽  
E. Freeman ◽  
L. P. Zawada
Keyword(s):  
High Temperature ◽  
Elevated Temperature ◽  
Room Temperature ◽  
Thermal Exposure ◽  
Strength Distribution ◽  
Tensile Behavior ◽  
Beneficial Effects ◽  
Elevated Temperature Tensile ◽  
Long Duration ◽  
Temperature Exposure

The tensile behavior of Nextel 720 fibers at elevated temperature was compared with room temperature results for both bare and monazite-coated fibers. While coated and uncoated fibers have nearly identical tensile strengths and Weibull moduli at room temperature, differences in response were seen at elevated temperature. Coated fibers tested at 1200°C were found to have a 40% drop in strength. Uncoated fibers at high temperature exhibited 55% less strength than at room temperature. However, the tensile strength distribution for uncoated fibers tested at high temperature exhibited two distinct populations, indicating two different failure mechanisms. One population showed a 50% drop while the other showed a 64% drop. The coating was thus found to have a protective effect in terms of short-duration high-temperature exposure. Further, the effect of soaking on strength was investigated by thermally soaking coated and uncoated fibers in air at 1200°C for 100 hours prior to tensile testing at elevated temperature. In this case, the long duration of thermal exposure appeared to eliminate the beneficial effects of the coating. Soaked fibers, both coated and uncoated, were found to have nearly identical strengths at 1200°C—a reduction of about 60%.

Elevated Temperature Tensile Behavior of Rheo-Cast 7075-T6 Al Alloy Produced by GISS Technique

2014 ◽  
Vol 881-883 ◽  
pp. 1597-1600 ◽  
Author(s):  
Narissara Mahathaninwong ◽  
Sirikul Wisutmethangoon ◽  
Thawatchai Plookphol ◽  
Jessada Wannasin ◽  
Suchart Chantaramanee
Keyword(s):  
Tensile Strength ◽  
Elevated Temperature ◽  
Ultimate Tensile Strength ◽  
Yield Strength ◽  
Room Temperature ◽  
Tensile Behavior ◽  
Al Alloy ◽  
Elevated Temperature Tensile ◽  
Semi Solid ◽  
Increasing Temperature

Tensile properties of rheo-cast 7075-T6 Al alloy produced by Gas Induced Semi-Solid (GISS) technique was investigated as a function of temperatures from 25°C to 250 °C in order to assess the potent of high temperature applications. It was found that the ultimate tensile strength and yield strength of the alloy decreased steadily with increasing temperature. There was loss in strength of about 33% at 200°C and 46% at 250 °C comparing to the strength at room temperature. At T = 250 °C, the ultimate tensile strength and yield strength of the rheo-cast 7075-T6 Al alloy were higher than those of the wrought 7075-T651 Al alloy. Keyword: 7075 Al alloy; Gas Induced Semi Solid (GISS) technique; Elevated temperature tensile.

Elevated temperature tensile behavior of Ti-25AI-10Nb-3V-1Mo

1995 ◽  
Vol 26 (3) ◽  
pp. 703-720 ◽  
Author(s):  
C. H. Ward ◽  
A. W. Thompson ◽  
J. C. Williams
Keyword(s):  
Elevated Temperature ◽  
Tensile Behavior ◽  
Elevated Temperature Tensile

Thermal Resistance of Fly Ash Geopolymers with Alumina as Additive

2018 ◽  
Vol 281 ◽  
pp. 182-188
Author(s):  
Yong Sing Ng ◽  
Yun Ming Liew ◽  
Cheng Yong Heah ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
Kamarudin Hussin
Keyword(s):  
Elevated Temperature ◽  
Fly Ash ◽  
Thermal Resistance ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Room Temperature ◽  
Strength Degradation ◽  
Alumina Addition ◽  
Higher Temperature ◽  
Temperature Exposure

The present work investigates the effect of alumina addition on the thermal resistance of fly ash geopolymers. Fly ash geopolymers were synthesised by mixing fly ash with activator solution (A mixture of 12M sodium hydroxide and sodium silicate) at fly ash/activator ratio of 2.5 and sodium silicate/sodium hydroxide ratio of 2.5. The alumina (0, 2 and 4 wt %) was added as an additive. The geopolymers were cured at room temperature for 24 hours and 60°C for another 24 hours. After 28 days, the geopolymers was heated to elevated temperature (200 - 1000°C). For unexposed geopolymers, the addition of 2 wt % of alumina increased the compressive strength of fly ash geopolymers while the strength decreased when the content increased to 4 wt.%. The temperature-exposed geopolymers showed enhancement of strength at 200°C regardless of the alumina content. The strength reduced at higher temperature exposure (> 200°C). Despite the strength degradation at elevated temperature, the strength attained was relatively high in the range of 13 - 45 MPa up to 1000°C which adequately for application as structural materials.

Three-Dimensional Numerical Analysis for Bolted Flange Joints Considering Effect of Creep

2018 ◽  
Author(s):  
Lewen Bi ◽  
Lanzhu Zhang
Keyword(s):  
High Temperature ◽  
Elevated Temperature ◽  
Numerical Analysis ◽  
Yield Strength ◽  
Room Temperature ◽  
Three Dimensional ◽  
Short Term ◽  
Flange Connection ◽  
Petroleum Chemical ◽  
Bolted Flange

Bolted flange joints are widely used in petroleum, chemical, nuclear and power industries, etc. With more and more devices are used at high temperature, the performance of flange connections becomes more complex, especially with creep of different components in flange connection. At elevated temperature, with the loss of bolt force and gasket force due to creep, the joints are prone to leak. Based on this, this paper analyzed the relaxation of bolt force at elevated temperature due to creep of bolt, flange and gasket separately and simultaneously. Besides, the influence of different initial installation stress of bolts was also studied. The results showed bolted flange joints relaxed due to gasket creep during early short term service. However, contribution of bolt and flange creep became more and more significant with the extension of time. With considering the creep of bolt, flange and gasket simultaneously, 50% to 60% of the bolt material yield strength at room temperature was recommended as the bolt initial installation stress for the joint case studied in this paper.

Microstructure Features of Cold-Sprayed NiCoCrAlTaY Coating and its High Temperature Oxidation Behavior

2011 ◽  
Vol 686 ◽  
pp. 595-602 ◽  
Author(s):  
Chang Jiu Li ◽  
Yong Li ◽  
Lu Kuo Xing ◽  
Guan Jun Yang ◽  
Cheng Xin Li
Keyword(s):  
High Temperature ◽  
Oxidation Behavior ◽  
Cold Spraying ◽  
Thermal Exposure ◽  
Isothermal Treatment ◽  
Temperature Oxidation ◽  
The Matrix ◽  
High Temperature Oxidation Behavior ◽  
Temperature Exposure ◽  
Sprayed Coating

Superalloy coating was deposited by cold-spraying using a commercial NiCoCrAlTaY powder. The coating microstructure was investigated by scanning electron microscopy and X-ray diffraction to reveal the change of the b-NiAl phase in the as-received powder particle during coating deposition. The oxidation behavior of the cold-sprayed MCrAlY coating and its microstructural evolution during the isothermal treatment were examined. The results show that significant microstructural change occurred to NiCoCrAlTaY superalloy during cold spraying and the thermal exposure. The intensive plastic deformation upon high velocity impact of spray particles results in transformation of b-NiAl to the matrix phase, forming metaltable b-NiAl depletion zones (b-PDZs) which are distributed around the boundaries of deposited particles in the coating. The central part of the deposited particles with limited deformation retained the original phase constitutions of the starting powder. The b-phase with fine grains is re-precipitated uniformly in the areas in b-PDZs in the as-sprayed coating during high temperature exposure. A stable Al2O3 scale was formed on cold-sprayed NiCoCrAlTaY during oxidation possibly due to active b-PDZs on the top surface of the coating.

Deformation of an extruded nickel beryllide between room temperature and 820 °C

1991 ◽  
Vol 6 (12) ◽  
pp. 2653-2659 ◽  
Author(s):  
G.M. Pharr ◽  
S.V. Courington ◽  
J. Wadsworth ◽  
T.G. Nieh
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Elevated Temperature ◽  
Flow Stress ◽  
Strain Hardening ◽  
Room Temperature ◽  
High Temperature Strength ◽  
Compression Tests ◽  
Tension And Compression ◽  
Better Than

The mechanical properties of nickel beryllide, NiBe, have been investigated in the temperature range 20–820 °C. The room temperature properties were studied using tension, bending, and compression tests, while the elevated temperature properties were characterized in compression only. NiBe exhibits some ductility at room temperature; the strains to failure in tension and compression are 1.3% and 13%, respectively. Fracture is controlled primarily by the cohesive strength of grain boundaries. At high temperatures, NiBe is readily deformable—strains in excess of 30% can be achieved at temperatures as low as 400 °C. Strain hardening rates are high, and the flow stress decreases monotonically with temperature. The high temperature strength of NiBe is as good or better than that of NiAl, but not quite as good as CoAl.

300C Capable Digital Integrated Circuits in SiC Technology

2012 ◽  
Vol 717-720 ◽  
pp. 1261-1264 ◽  
Author(s):  
Amita Patil ◽  
Naresh Rao ◽  
Vinayak Tilak
Keyword(s):  
Silicon Carbide ◽  
High Temperature ◽  
Elevated Temperature ◽  
Integrated Circuits ◽  
Room Temperature ◽  
Continuous Operation ◽  
Shift Register ◽  
Digital Integrated Circuits ◽  
Enhancement Mode

This paper pertains to development of high temperature capable digital integrated circuits in n-channel, enhancement-mode Silicon Carbide (SiC) MOS technology. Among the circuits developed in this work are data latch, flip flops, 4-bit shift register and ripple counter. All circuits are functional from room temperature up to 300C without any notable degradation in performance at elevated temperature. The 4-bit counter demonstrated stable behavior for over 500 hours of continuous operation at 300C.

Tough, Ductile High-Temperature Intermetallic Compounds: Results of a Four-Year Survey.

1990 ◽  
Vol 213 ◽  
Author(s):  
R.L. Fleischer ◽  
C.L. Briant ◽  
R.D. Field
Keyword(s):  
High Temperature ◽  
Intermetallic Compounds ◽  
Room Temperature ◽  
Impact Resistance ◽  
High Strength ◽  
Aircraft Engine ◽  
High Temperature Strength ◽  
Beneficial Effects ◽  
Strength And Stiffness ◽  
Binary Compounds

ABSTRACTA four-year survey of high-temperature intermetallic compounds has been aimed at identifying potentially useful structural materials for aerospace and aircraft engine applications. Since the good properties of high strength and stiffness at high temperatures are typically negated by brittleness at ambient temperature, new materials must have roomtemperature toughness or ductility. Screening has been done of 90 binary compounds with 20 different crystal structures, and 130 ternary or higher-order alloys. Testing typically included hardness vs. temperature, elastic modulus determination, and toughness evaluation via a room-temperature chisel test. Four alloy systems, including only two types that are of the simplest structures, showed substantial room-temperature toughness: Al-Ru, Ru-Sc, Ir-Nb, and Ru-Ta. Of these the last and the first are the most promising. Special features of the Ru- Ta (L1o) alloys are their room-temperature impact resistance and high-temperature strength. AIRu (B2) alloys can be tougher than the L1o structures and most are also ductile in compression at room temperature. Alloying experiments with B, Cr, and Sc show beneficial effects on ductility, oxidation resistance, and high-temperature strength.

FANSTEEL 80 METAL

Alloy Digest ◽  
1981 ◽  
Vol 30 (11) ◽  
Keyword(s):  
Fracture Toughness ◽  
Corrosion Resistance ◽  
Electron Beam ◽  
High Temperature ◽  
Elevated Temperature ◽  
Electron Beam Melting ◽  
Room Temperature ◽  
Base Alloy ◽  
Heat Treating ◽  
High Quality

Abstract FANSTEEL 80 METAL is a columbium-base alloy containing nominally 1% zirconium. It is produced by electron-beam melting which gives it exceptionally high interstitial purity. It is several times stronger than pure columbium at elevated temperature; and this is without sacrificing the ease of fabrication associated with columbium. Fansteel 80 Metal can be fabricated easily at room temperature and high-quality ductile welds are possible. Its applications include nuclear, liquid metal loops and structures for high-temperature environments. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: Cb-10. Producer or source: Fansteel Metallurgical Corporation. Originally published August 1966, revised November 1981.

Influence of Alumina Particles on Tribology of Autocatalytic Ni-P Coatings at High Temperature

2021 ◽  
Vol 9 (1) ◽  
pp. 1-25
Author(s):  
Sanjib Kundu ◽  
Suman Kalyan Das ◽  
Prasanta Sahoo
Keyword(s):  
High Temperature ◽  
Elevated Temperature ◽  
Room Temperature ◽  
Adhesive Wear ◽  
Amorphous Structure ◽  
Nanocrystalline And Amorphous ◽  
Alumina Particles ◽  
Al2o3 Particles ◽  
Electroless Ni ◽  
Worn Surface

The present work considers the effects of incorporation of hard Al2O3 particles on the structure, microhardness, and tribological behavior of electroless Ni-P coatings at room temperature and elevated temperature. Ni-P (9% P) coating shows a typical amorphous structure that changes to a mixture of nanocrystalline and amorphous structure due to the addition of alumina particles. The incorporation of Al2O3 particles is found to enhance the overall hardness and wear resistance of the Ni-P coating. Exposure to high temperature during tribological tests acts as brief heat treatment, initiating microstructural changes in the coating which further increases the hardness of the deposit. The scanning electron micrograph of the worn surface of the coating reveals both abrasive and adhesive wear phenomena governing the wear mechanism at elevated temperature. The development of the oxide layer is another important characteristic of the coatings examined under high temperatures (around 500°C).

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