Application of TEM to Deformation, Wear, and Fracture of Ceramics

1974 ◽  
Vol 32 ◽  
pp. 472-473
Author(s):  
B. J. Hockey
Keyword(s):  
Wear Resistance ◽  
High Temperature ◽  
Mechanical Behavior ◽  
Brittle Materials ◽  
High Temperature Strength ◽  
Wide Range ◽  
Corrosive Environments ◽  
Further Development

Ceramics, such as Al2O3 and SiC have numerous current and potential uses in applications where high temperature strength, hardness, and wear resistance are required often in corrosive environments. These materials are, however, highly anisotropic and brittle, so that their mechanical behavior is often unpredictable. The further development of these materials will require a better understanding of the basic mechanisms controlling deformation, wear, and fracture.The purpose of this talk is to describe applications of TEM to the study of the deformation, wear, and fracture of Al2O3. Similar studies are currently being conducted on SiC and the techniques involved should be applicable to a wide range of hard, brittle materials.

scholarly journals High Temperature Performance of Spark Plasma Sintered W0.5(TaTiVCr)0.5 Alloy

Metals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1512 ◽  
Author(s):  
Sajid Alvi ◽  
Owais Ahmed Waseem ◽  
Farid Akhtar
Keyword(s):  
Wear Resistance ◽  
Compressive Strength ◽  
High Temperature ◽  
Phase Stability ◽  
Tungsten Alloy ◽  
Compressive Yield Strength ◽  
High Temperature Strength ◽  
Secondary Phases ◽  
High Temperature Xrd ◽  
Spark Plasma

The phase stability, compressive strength, and tribology of tungsten alloy containing low activation elements, W0.5(TaTiVCr)0.5, at elevated temperature up to 1400 °C were investigated. The spark plasma sintered W0.5(TaTiVCr)0.5 alloy showed body centered cubic (BCC) structure, which was stable up to 1400 °C using in-situ high temperature XRD analysis and did not show formation of secondary phases. The W0.5(TaTiVCr)0.5 alloy showed exceptionally high compressive yield strength of 1136 ± 40 MPa, 830 ± 60 MPa and 425 ± 15 MPa at 1000 °C, 1200 °C and 1400 °C, respectively. The high temperature tribology at 400 °C showed an average coefficient of friction (COF) and low wear rate of 0.55 and 1.37 × 10−5 mm3/Nm, respectively. The superior compressive strength and wear resistance properties were attributed to the solid solution strengthening of the alloy. The low activation composition, high phase stability, superior high temperature strength, and good wear resistance at 400 °C of W0.5(TaTiVCr)0.5 suggest its potential utilization in extreme applications such as plasma facing materials, rocket nozzles and industrial tooling.

THYROTHERM 2999

Alloy Digest ◽  
2008 ◽  
Vol 57 (5) ◽  
Keyword(s):  
Wear Resistance ◽  
High Temperature ◽  
Physical Properties ◽  
Heat Treating ◽  
High Temperature Strength ◽  
Temperature Performance

Abstract Thyrotherm 2999 exhibits high-temperature strength with wear resistance. This datasheet provides information on composition, physical properties, and hardness. It also includes information on high temperature performance as well as forming and heat treating. Filing Code: TS-665. Producer or source: Schmolz + Bickenbach USA Inc.

Composition and microstructure of a nickel-base superalloy, UDIMET 720

1989 ◽  
Vol 47 ◽  
pp. 280-281
Author(s):  
k.L. More ◽  
M.K. Miller
Keyword(s):  
High Temperature ◽  
Grain Boundaries ◽  
Analytical Electron Microscopy ◽  
Grain Boundary Sliding ◽  
Nickel Base Superalloy ◽  
High Temperature Strength ◽  
Phase Form ◽  
Wide Range ◽  
Nickel Base ◽  
Udimet 720

A wide range of nickel-base superalloys are currently used for land- and marine-based turbines. Small amounts of carbon and boron are added to improve the high temperature mechanical properties of these alloys. During a standard heat treatment, large carbides evolve at the grain and twin boundaries and small, intragranular precipitates of the γ′phase form. It has been proposed that the carbides improve the high temperature strength by inhibiting grain boundary sliding. The role of boron is, however, not fully understood. Decker suggests that boron stabilizes the γ′ precipitates and prevents the formation of denuded zones at the grain boundaries thus inhibiting microcrack formation at transverse grain boundaries. The purpose of this study was twofold; to characterize the microstructure of Udimet 720 using atom probe field-ion microscopy (APFIM), analytical electron microscopy (AEM), and secondary ion mass spectroscopy (SIMS) and to determine if boron and carbon segregate to boundaries and γ/γ′interfaces. This is a continuation of work started by Burke et al.

MA276

Alloy Digest ◽  
2014 ◽  
Vol 63 (4) ◽  
Keyword(s):  
Fracture Toughness ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Heat Treating ◽  
Corrosion Resistant ◽  
Temperature Performance ◽  
Wide Range ◽  
Corrosion Resistant Alloy ◽  
Nickel Base ◽  
Corrosive Environments

Abstract MA276 is a Ni-16Cr-16Mo-5Fe-4W (mass %) nickel-base corrosion-resistant alloy superior in a wide range of corrosive environments. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as fracture toughness. It also includes information on low and high temperature performance, and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Ni-711. Producer or source: MMC Superalloy Corporation.

UHB ROLAND

Alloy Digest ◽  
1976 ◽  
Vol 25 (2) ◽  
Keyword(s):  
Fracture Toughness ◽  
Wear Resistance ◽  
High Temperature ◽  
Physical Properties ◽  
Surface Treatment ◽  
Thermal Shock ◽  
Thermal Fatigue ◽  
Heat Treating ◽  
High Temperature Strength ◽  
Good Resistance

Abstract UHB ROLAND is a chromium-molybdenum-cobalt-vanadium tool steel characterized by good resistance to thermal shock and thermal fatigue, good high-temperature strength, good wear resistance and good machinability. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on forming, heat treating, machining, joining, and surface treatment. Filing Code: TS-296. Producer or source: Uddeholm Aktiebolag.

Mechanical Behavior of Quasicrystals

MRS Bulletin ◽  
1997 ◽  
Vol 22 (11) ◽  
pp. 65-68 ◽  
Author(s):  
Knut Urban ◽  
Michael Feuerbacher ◽  
Markus Wollgarten
Keyword(s):  
Mechanical Properties ◽  
Wear Resistance ◽  
High Temperature ◽  
Low Temperature ◽  
Mechanical Behavior ◽  
Melting Temperature ◽  
Sliding Friction ◽  
Great Promise ◽  
Brittle To Ductile Transition ◽  
Physical Reasons

Scientists have studied the mechanical properties of quasicrystalline materials for quite some time. However the difficulty in obtaining material of reasonable quality hampered systematic investigations. The progress in materials preparation in recent years has triggered new activity in this field. Furthermore the new ternary and multicomponent alloys have demonstrated great promise for use as coatings with good wear resistance and low coefficients of sliding friction. However the physical reasons for these properties and their correlation with the particular structure of quasicrystals are still not understood. As in conventional alloys, experiments under well-defined conditions are required that can serve as a basis for understanding the intrinsic mechanical properties of quasicrystals. Such studies are now increasingly possible after the development of techniques to grow larger single quasicrystals up to a few centimeters in size directly from the melt.Since the mechanical behavior of quasicrystalline alloys is to a great extent determined by a brittle-to-ductile transition at about 70% of the absolute melting temperature, it is useful to discuss the mechanical properties with reference to appropriately defined low-temperature and high-temperature regions.

Quantification of High Temperature Strength of Nickel-Based Superalloys

2007 ◽  
Vol 546-549 ◽  
pp. 1319-1326 ◽  
Author(s):  
Zhan Li Guo ◽  
N. Saunders ◽  
Alfred Peter Miodownik ◽  
J.P. Schille
Keyword(s):  
Solid Solution ◽  
High Temperature ◽  
Tensile Deformation ◽  
Model Development ◽  
High Temperature Strength ◽  
Solid Solution Strengthening ◽  
Wide Range ◽  
Solution Strengthening ◽  
Deformation Modes ◽  
Good Agreement

The strength of nickel-based superalloys usually consists of solid solution strengthening from the gamma matrix and precipitation hardening due to the gamma' and/or gamma" precipitates. In the present work, a model was developed to calculate the high temperature strength of nickel-based superalloys, where the temperature dependence of each strengthening contribution was accounted for separately. The high temperature strength of these alloys is not only a function of microstructural changes in the material, but the result of a competition between two deformation modes, i.e. the normal low to mid temperature tensile deformation and deformation via a creep mode. Extensive validation had been carried out during the model development. Good agreement between calculated and experimental results has been achieved for a wide range of nickel-based superalloys, including solid solution alloys and precipitation-hardened alloys with different type/amount of precipitates. This model has been applied to two newly developed superalloys and is proved to be able to make predictions to within useful accuracy.

High Temperature Corrosion in Refinery And Petrochemical Service

CORROSION ◽  
1960 ◽  
Vol 16 (12) ◽  
pp. 593t-600t ◽  
Author(s):  
E. N. SKINNER ◽  
J. F. MASON ◽  
J. J. MORAN
Keyword(s):  
Corrosion Resistance ◽  
High Temperature ◽  
Mechanical Behavior ◽  
Elevated Temperatures ◽  
High Temperature Corrosion ◽  
Residual Oil ◽  
The Common ◽  
Engineering Alloys ◽  
Corrosive Environments ◽  
Selection Of

Abstract The paper is concerned with the corrosion phenomena likely to influence the selection of materials for refinery service at elevated temperatures. The problems of oxidation, sulfidation and carburization are discussed in detail and consideration is given to the effects of condensate corrosion and residual oil ash corrosion. The contributions of various alloying elements in the common engineering alloys to their physical and mechanical behavior as well as to their corrosion resistance at elevated temperatures are discussed. Basic considerations for the selection of suitable alloys to withstand high temperature corrosive environments are outlined. 8.4.3

How hard metal becomes soft: crystallographic analysis on the mechanical behavior of ultra-coarse cemented carbide

2019 ◽  
Vol 75 (6) ◽  
pp. 1014-1023 ◽  
Author(s):  
Huaxin Hu ◽  
Xuemei Liu ◽  
Chao Hou ◽  
Haibin Wang ◽  
Fawei Tang ◽  
...  
Keyword(s):  
High Temperature ◽  
Mechanical Behavior ◽  
Microstructural Characterization ◽  
Hard Metal ◽  
Crystallographic Analysis ◽  
Cemented Carbide ◽  
Coarse Grained ◽  
High Temperature Strength ◽  
Slip Systems ◽  
Dislocation Reaction

Investigation into the temperature dependence of the mechanical behavior of ultra-coarse grained cemented carbide materials is highly demanded due to its service conditions of concurrent applied stress and high temperature. In the present study, based on the designed experiments and microstructural characterization combined with crystallographic analysis, the evolution of slip systems, motion and interaction of dislocations with temperature are quantified for the WC hard phase. Mechanisms are proposed for the formation of the sessile dislocations in the main slip systems at the room temperature and the glissile dislocations in the new slip systems activated at high temperatures. Furthermore, the correlation of the plastic strain and fracture toughness with the temperature-dependent slip activation, dislocation reaction and transformation is explained quantitatively. Enlightened by the present findings, potential approach to enhance the high-temperature strength of ultra-coarse cemented carbides based on WC strengthening was suggested.

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