Investigation of long-term aging of high-temperature Nb-matrix composite material reinforced by α-Al2O3 fibers

2021 ◽  
Vol 5 ◽  
pp. 28-38
Author(s):  
B. V. Shchetanov ◽  
◽  
D. V. Graschenkov ◽  
R. M. Dvoretskov ◽  
A. N. Bol’shakova ◽  
...  
Keyword(s):  
High Temperature ◽  
Interphase Boundary ◽  
Bending Strength ◽  
High Heat ◽  
Original Sample ◽  
Initial Sample ◽  
Average Hardness ◽  
Crystal Fibers ◽  
Α Al2o3

Solving the problems when developing high-temperature composite materials (HTCM) requires non-standard approaches, as for example, using the long-term high-heat treatment (HHT), which has a significant effect on mechanical properties of the HTCM at high temperatures. To obtain a niobium-based HTCM reinforced with α-Al2O3 single crystal fibers (“Nb – SCF α-Al2O3”) hot pressing technique was used in the research. The HHT effect at 1350 °C of the HTCM on its high-temperature (1300 °C) bending strength, hardness and density at 22 °C after 100 hours HHT with a step in 25 hours was investigated. The samples structure and elements distribution at the interfacial boundaries of HTCMs were studied. It was established that the elements interdiffusion width at the interphase boundary of the continuous composition “Nb – SCF α-Al2O3” doesn’t exceed 2 μm for the whole HHT term; in outside the interphase boundary, only niobium oxides and carbides were detected. It was found that the bending strength after 25 hours HHT slightly exceeded the strength of the initial sample (before HHT); with further high-temperature HHT, the strength increased by 1.7 – 2 times in comparison with the initial sample. The hardness (HV 0.5) after 25 hours HHT remained actually unchanged (70), and subsequently sharply increased and the average hardness in three aging stages (50, 75 and 100 hours) was 330. The density of HTCMs increased with HHT, and after 100 hours HHT increased in comparison with the original sample by 1.3 times.

Physical Properties of Selected Silicates for a Long-Term Heat Container

2018 ◽  
Vol 276 ◽  
pp. 154-159
Author(s):  
Stanislav Šťastník ◽  
Jiří Vala ◽  
František Šot
Keyword(s):  
High Temperature ◽  
Physical Properties ◽  
High Heat ◽  
Thermal Source ◽  
Temperature Changes ◽  
Measurement Methodology ◽  
Wire Method ◽  
High Heat Capacity ◽  
Basic Prerequisite

Implementation of high temperature solar reservoirs is associated with problems related to the physical properties of materials, especially with temperature resistance of the material at temperature changes, with high heat capacity, with high thermal conductivity and with material fire resistance. In the case of silicate materials, more specific materials with favourable physical properties are available, which can be used for the construction of high temperature containers. The basic prerequisite for designing such container is the knowledge of the physical properties of the heat storage core and the thermal insulation ability of container cladding layers.The paper deals with the problem of identification of material properties of silicates in the wide temperature range up to 800 °C, using the standard measurement methodology, improved by additional temperature recording at a defined distance from the thermal source during the dynamic thermal development of the linear thermal source, well-known as the hot wire method.

Microstructural characterization of a rapidly solidified Al-Fe-V-Si alloy for elevated temperature applications

1988 ◽  
Vol 46 ◽  
pp. 550-551
Author(s):  
R. E. Franck ◽  
J. A. Hawk ◽  
G. J. Shiflet
Keyword(s):  
High Temperature ◽  
Elevated Temperature ◽  
Grain Growth ◽  
Volume Fraction ◽  
Microstructural Characterization ◽  
Second Phase ◽  
Microstructural Stability ◽  
Elevated Temperature Strength ◽  
Temperature Applications

Rapid solidification processing (RSP) is one method of producing high strength aluminum alloys for elevated temperature applications. Allied-Signal, Inc. has produced an Al-12.4 Fe-1.2 V-2.3 Si (composition in wt pct) alloy which possesses good microstructural stability up to 425°C. This alloy contains a high volume fraction (37 v/o) of fine nearly spherical, α-Al12(Fe, V)3Si dispersoids. The improved elevated temperature strength and stability of this alloy is due to the slower dispersoid coarsening rate of the silicide particles. Additionally, the high v/o of second phase particles should inhibit recrystallization and grain growth, and thus reduce any loss in strength due to long term, high temperature annealing.The focus of this research is to investigate microstructural changes induced by long term, high temperature static annealing heat-treatments. Annealing treatments for up to 1000 hours were carried out on this alloy at 500°C, 550°C and 600°C. Particle coarsening and/or recrystallization and grain growth would be accelerated in these temperature regimes.

KUBOTA KNC-03

Alloy Digest ◽  
2010 ◽  
Vol 59 (1) ◽  
Keyword(s):  
Compressive Strength ◽  
High Temperature ◽  
Physical Properties ◽  
Tensile Properties ◽  
High Strength ◽  
Temperature Performance ◽  
Resistance To Oxidation

Abstract Kubota KNC-03 is a grade with a combination of high strength and excellent resistance to oxidation. These properties make this alloy suitable for long-term service at temperature up to 1250 deg C (2282 deg F). This datasheet provides information on physical properties, hardness, elasticity, tensile properties, and compressive strength as well as creep. It also includes information on high temperature performance as well as casting and joining. Filing Code: Ni-676. Producer or source: Kubota Metal Corporation, Fahramet Division. See also Alloy Digest Ni-662, April 2008.

PRESSURDIE-1

Alloy Digest ◽  
1967 ◽  
Vol 16 (4) ◽  
Keyword(s):  
High Temperature ◽  
Die Casting ◽  
Heat Treating ◽  
High Heat ◽  
Strength Properties ◽  
High Temperature Strength ◽  
High Heat Resistance ◽  
Die Steel ◽  
Temperature Performance ◽  
Steel Industries

Abstract PRESSURDIE-1 is an air-hardening hot work tool and die steel having high heat resistance and good high temperature strength properties. It is recommended for die casting dies, extrusion and forging dies. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on high temperature performance as well as forming, heat treating, machining, and joining. Filing Code: TS-191. Producer or source: Continental Copper & Steel Industries Inc..

ATI 6-2-4-2

Alloy Digest ◽  
2020 ◽  
Vol 69 (8) ◽  
Keyword(s):  
Tensile Strength ◽  
Titanium Alloy ◽  
High Temperature ◽  
Creep Strength ◽  
High Strength ◽  
Heat Treating ◽  
Good Combination ◽  
Long Term Stability ◽  
Temperature Performance

Abstract ATI 6-2-4-2 is a near-alpha, high strength, titanium alloy that exhibits a good combination of tensile strength, creep strength, toughness, and long-term stability at temperatures up to 425 °C (800 °F). Silicon up to 0.1% frequently is added to improve the creep resistance of the alloy. This datasheet provides information on composition, physical properties, hardness, and tensile properties as well as creep. It also includes information on high temperature performance as well as forming, heat treating, machining, and joining. Filing Code: Ti-169. Producer or Source: ATI.

PEERLESS LCT2

Alloy Digest ◽  
1963 ◽  
Vol 12 (11) ◽  
Keyword(s):  
Fracture Toughness ◽  
High Temperature ◽  
Elevated Temperatures ◽  
Heat Treating ◽  
High Heat ◽  
High Heat Resistance ◽  
Steel Company ◽  
Temperature Performance ◽  
Crucible Steel ◽  
High Degree

Abstract PEERLESS LCT2 is a hot work steel which possesses high heat resistance and a high degree of working hardness at elevated temperatures. This steel is best applied where hardness and resistance to abrasion are of more importance than toughness. This datasheet provides information on composition, physical properties, hardness, and tensile properties as well as fracture toughness. It also includes information on high temperature performance as well as forming, heat treating, and machining. Filing Code: TS-140. Producer or source: Crucible Steel Company of America.

CRUCIBLE 309

Alloy Digest ◽  
1982 ◽  
Vol 31 (4) ◽  
Keyword(s):  
Fracture Toughness ◽  
High Temperature ◽  
Physical Properties ◽  
Heat Treating ◽  
High Heat ◽  
Nickel Steel ◽  
Annealed Condition ◽  
Temperature Performance ◽  
Cold Worked ◽  
Specialty Metals

Abstract CRUCIBLE 309 is a non-hardenable austenitic chromium-nickel steel that has high heat-resisting characteristics. In the annealed condition it is non-magnetic or magnetic, depending on the composition. When cold worked it is very slightly magnetic. Typical applications include aircraft heaters and sulfite liquor handling equipment. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness and creep. It also includes information on high temperature performance as well as heat treating, machining, and joining. Filing Code: SS-405. Producer or source: Crucible Specialty Metals Division, Colt Industries.

ARMCO 25-12

Alloy Digest ◽  
1955 ◽  
Vol 4 (7) ◽  
Keyword(s):  
Fracture Toughness ◽  
Stainless Steel ◽  
Corrosion Resistance ◽  
High Temperature ◽  
High Strength ◽  
Heat Treating ◽  
High Heat ◽  
Temperature Performance ◽  
Aisi Type ◽  
Lower Carbon

Abstract ARMCO 25-12 is an austenitic chromium-nickel stainless steel with high heat resisting qualities, high strength and creep values up to 2000 F. It is equivalent to AISI Type 309 stainless steel; and in the lower carbon grade is equivalent to AISI Type 309S. This datasheet provides information on composition, physical properties, hardness, elasticity, 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 forming, heat treating, machining, and joining. Filing Code: SS-32. Producer or source: Armco Inc., Eastern Steel Division.

DH31-S

Alloy Digest ◽  
2003 ◽  
Vol 52 (4) ◽  
Keyword(s):  
Shear Strength ◽  
High Temperature ◽  
High Strength ◽  
Heat Treating ◽  
High Heat ◽  
Steel Company ◽  
Die Steel ◽  
Temperature Performance ◽  
Hot Working Die Steel ◽  
Check Resistance

Abstract Hot-working die steel DH31-S has high strength, toughness, and high heat check resistance. This datasheet provides information on physical properties, elasticity, tensile properties, and shear strength. It also includes information on high temperature performance as well as heat treating. Filing Code: TS-600. Producer or source: International Mold Steel Inc., Daido Steel Company Ltd.

scholarly journals CO Detection Investigation at High Temperature by SiC MISFET Metal/Oxide Gas Sensors

Proceedings ◽  
2021 ◽  
Vol 56 (1) ◽  
pp. 41
Author(s):  
Lida Khajavizadeh ◽  
Anita Lloyd Spetz ◽  
Mike Andersson
Keyword(s):  
High Temperature ◽  
Gas Sensors ◽  
Elevated Temperatures ◽  
Long Term Stability ◽  
Stability Performance ◽  
Catalytic Metal ◽  
Co Detection ◽  
Effect Transistor ◽  
Metal Oxide Gas Sensors

In order to investigate the necessary device improvements for high-temperature CO sensing with SiC metal insulator semiconductor field effect transistor (MISFET)-based chemical gas sensors, devices employing, as the gas-sensitive gate contact, a film of co-deposited Pt/Al2O3 instead of the commonly used catalytic metal-based contacts were fabricated and characterized for CO detection at elevated temperatures and different CO and O2 levels. It can be concluded that the sensing mechanism at elevated temperatures correlates with oxygen removal from the sensor surface rather than the surface CO coverage as observed at lower temperatures. The long-term stability performance was also shown to be improved compared to that of previously studied devices.

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