scholarly journals The Mechanism of High-Strength Quenching-Partitioning-Tempering Martensitic Steel at Elevated Temperatures

Crystals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 94 ◽  
Author(s):  
Ke Zhang ◽  
Maoyuan Zhu ◽  
Bitong Lan ◽  
Ping Liu ◽  
Wei Li ◽  
...  
Keyword(s):  
Retained Austenite ◽  
Elevated Temperatures ◽  
Martensitic Steel ◽  
Lath Martensite ◽  
Temperature Stability ◽  
High Strength ◽  
High Temperature Stability ◽  
High Deformation ◽  
Heat Treated ◽  
The Relationship

High-strength medium-carbon martensitic steel was heat treated through a quenching-partitioning-tempering (Q-P-T) treatment. Both the mechanism for improved ductility and the high temperature stability of austenite were investigated. The Q-P-T martensitic steel showed good products of strength and elongation (PSE) at various deformation temperatures ranging within 25–350 °C. The optimum PSE value (>57,738 MPa%) was achieved at 200 °C. The microstructure of the Q-P-T steel is constituted of laths martensite with dislocations, retained austenite located within lath martensite and small niobium carbides (NbC), and/or transitional ε-carbides that precipitated in the lath martensite. The good ductility can be mainly attributed to the laminar-like austenite that remained within the lath-martensite. The austenite can effectively enhance ductility through the effect of dislocation absorption by the retained austenite and through transformation-induced plasticity. The relationship between the microstructures and mechanical properties was investigated at high deformation temperatures.

SMITHS Ti-6Al-2Sn-4Zr-2Mo-Si

Alloy Digest ◽  
2021 ◽  
Vol 70 (12) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Titanium Alloy ◽  
High Temperature ◽  
Creep Resistance ◽  
Elevated Temperatures ◽  
Temperature Stability ◽  
High Strength ◽  
Heat Treating ◽  
High Temperature Stability ◽  
Alpha Titanium

Abstract Smiths Ti-6Al-2Sn-4Zr-2Mo-Si is a near-alpha titanium alloy that was developed for use at elevated temperatures. It exhibits high strength and toughness, excellent creep resistance, and high temperature stability at temperatures up 550 °C (1020 °F). This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as casting, heat treating, and joining. Filing Code: Ti-185. Producer or source: Smiths Metal Centres Limited.

Microstructure of resistance spot welding of maraging steels

1990 ◽  
Vol 48 (4) ◽  
pp. 900-901
Author(s):  
I. Neuman ◽  
S.F. Dirnfeld ◽  
I. Minkoff
Keyword(s):  
Maraging Steel ◽  
Spot Welding ◽  
Lath Martensite ◽  
Base Material ◽  
Aging Treatment ◽  
High Strength ◽  
Maraging Steels ◽  
Heat Treated ◽  
Current Cycle ◽  
Welding Processes

Experimental work on the spot welding of Maraging Steels revealed a surprisingly low level of strength - both in the as welded and in aged conditions. This appeared unusual since in the welding of these materials by other welding processes (TIG,MIG) the strength level is almost that of the base material. The maraging steel C250 investigated had the composition: 18wt%Ni, 8wt%Co, 5wt%Mo and additions of Al and Ti. It has a nominal tensile strength of 250 KSI. The heat treated structure of maraging steel is lath martensite the final high strength is reached by aging treatment at 485°C for 3-4 hours. During the aging process precipitation takes place of Ni3Mo and Ni3Ti and an ordered solid solution containing Co is formed.Three types of spot welding cycles were investigated: multi-pulse current cycle, bi-pulse cycle and single pulsle cycle. TIG welded samples were also tested for comparison.The microstructure investigations were carried out by SEM and EDS as well as by fractography. For multicycle spot welded maraging C250 (without aging), the dendrites start from the fusion line towards the nugget centre with an epitaxial growth region of various widths, as seen in Figure 1.

FEDERATED F401.5Ni

Alloy Digest ◽  
1974 ◽  
Vol 23 (12) ◽  
Keyword(s):  
Fracture Toughness ◽  
Elevated Temperatures ◽  
High Strength ◽  
Heat Treating ◽  
Casting Alloy ◽  
Aluminum Casting ◽  
Aluminum Casting Alloy ◽  
Treated Condition ◽  
Heat Treated ◽  
Heat Treated Condition

Abstract FEDERATED F401.5Ni is a heat-treatable aluminum casting alloy with high strength and good wear resistance in the fully heat-treated condition. It is recommended for castings requiring good strength at elevated temperatures. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as casting, heat treating, machining, and joining. Filing Code: Al-212. Producer or source: Federated Metals Corporation, ASARCO Inc..

UNS R54620

Alloy Digest ◽  
1987 ◽  
Vol 36 (7) ◽  
Keyword(s):  
Titanium Alloy ◽  
High Temperature ◽  
Time Use ◽  
Temperature Stability ◽  
High Strength ◽  
Heat Treating ◽  
High Temperature Stability ◽  
Beta Titanium Alloy ◽  
Beta Titanium ◽  
Long Time

Abstract UNS No. R54620 is an alpha-beta titanium alloy. It has an excellent combination of tensile strength, creep strength, toughness and high-temperature stability that makes it suitable for service to 1050 F. It is recommended for use where high strength is required. It has outstanding advantages for long-time use at temperatures to 800 F. This datasheet provides information on composition, physical properties, elasticity, tensile properties, and bend strength 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: Ti-86. Producer or source: Titanium alloy mills.

Comparative Assessment of Sporophyte and Gametophyte Thermal Resistance of Winter Rape

2019 ◽  
pp. 15-22
Keyword(s):  
Elevated Temperatures ◽  
Rapid Assessment ◽  
Temperature Stability ◽  
Temperature Factor ◽  
Plant Genome ◽  
Limiting Factors ◽  
Initial Assessment ◽  
High Temperature Stability ◽  
Winter Rape ◽  
High Yields

The temperature factor is one of the limiting factors for obtaining high yields of crops, so one of the main tasks of selection is to search for temperature-resistant genotypes and to create on their basis the banks of crops with high temperature stability. The first step to solving this problem is to conduct a rapid assessment of the temperature plasticity of large populations and to isolate breeding-valuable genotypes from them. There are numerous methods that allow, in the short term with minimal technical and material costs, to carry out an initial assessment of a large number of genotypes at sporophytic level and differentiate them by resistance to the temperature factor. These methods include the method of estimating pollen populations. These studies have repeatedly been conducted on many cultures, their correctness is due to the expression of a large part of the plant genome, both at the diploid and haploid levels of development and demonstrated by many studies in this direction. The aim of our study was to study the stability of gametophyte and sporophyte of collecting varieties and varieties of winter rape to elevated temperatures, to study the correlation between the heat resistance of sporophyte and gametophyte.

A new effect of retained austenite on ductility enhancement in high-strength quenching–partitioning–tempering martensitic steel

2011 ◽  
Vol 528 (29-30) ◽  
pp. 8486-8491 ◽  
Author(s):  
Ke Zhang ◽  
Meihan Zhang ◽  
Zhenghong Guo ◽  
Nailu Chen ◽  
Yonghua Rong
Keyword(s):  
Retained Austenite ◽  
Martensitic Steel ◽  
High Strength

Stability of Nanometer-Thick Layers in Hard Coatings

MRS Bulletin ◽  
2003 ◽  
Vol 28 (3) ◽  
pp. 169-172 ◽  
Author(s):  
Scott A. Barnett ◽  
Anita Madan ◽  
Ilwon Kim ◽  
Keith Martin
Keyword(s):  
High Temperature ◽  
Elevated Temperatures ◽  
Temperature Stability ◽  
Hexagonal Wurtzite Structure ◽  
Thin Layers ◽  
Hard Coatings ◽  
High Temperature Stability ◽  
The Stability ◽  
Hardness Values ◽  
Thick Layers

AbstractThis article reviews two topics related to the stability of hard coatings composed of nanometer-thick layers: epitaxial stabilization and high-temperature stability. Early work on nanolayered hard coatings demonstrated large hardness increases as compared with monolithic coatings, but it was subsequently found that the layers interdiffused at elevated temperatures. More recently, it has been shown that nanolayers exhibit good stability at elevated temperatures if the layer materials are thermodynamically stable with respect to each other and are able to form low-energy coherent interfaces. This article discusses metal/nitride, nitride/nitride, and nitride/boride nanolayers that exhibit good high-temperature stability and hardness values that are maintained (or even increase) after high-temperature annealing. Epitaxial stabilization of nonequilibrium structuresin thin layers is a well-known phenomenon that has been applied to hard nitride materials. In particular, AlN, which crystallizes in the hexagonal wurtzite structure in bulk form, was stabilized in the rock-salt cubic structure in nitride/nitride nanolayers (e.g., AlN/TiN). These results and the current understanding of epitaxial stabilization in hard nanolayers are discussed.

High Temperature Oxidation and Corrosion of Silicon-Based Non-Oxide Ceramics

1999 ◽  
Vol 122 (1) ◽  
pp. 13-18 ◽  
Author(s):  
H. Klemm ◽  
M. Herrmann ◽  
C. Schubert
Keyword(s):  
High Temperature ◽  
Elevated Temperatures ◽  
Microstructural Analysis ◽  
Temperature Stability ◽  
Ambient Air ◽  
High Temperature Stability ◽  
Temperature Oxidation ◽  
Sic Ceramics ◽  
Silicon Based

The present study is focussed on the oxidation behavior of nonoxide silicon-based ceramics. Various Si3N4 and SiC ceramics were examined after long term oxidation tests (up to 5000 h) at 1500°C in ambient air. The damage mechanisms were discussed on the basis of a comprehensive chemical and microstructural analysis of the materials after the oxidation tests. The diffusion of oxygen into the material and its further reaction in the bulk of the material were found to be the most critical factors during long term oxidation treatment at elevated temperatures. However, the resulting damage in the microstructure of the materials can be significantly reduced by purposeful microstructural engineering. Using Si3N4/SiC and Si3N4/MoSi2 composite materials provides the possibility to improve the high temperature stability. [S0742-4795(00)00301-X]

Design of SAW Specific Gas Sensor with High Sensitivity

2013 ◽  
Vol 303-306 ◽  
pp. 137-142
Author(s):  
Jin Yi Ma ◽  
Jing Yang ◽  
Bo Du ◽  
Lu Wang ◽  
Hong Min Jiang ◽  
...  
Keyword(s):  
High Temperature ◽  
Acoustic Wave ◽  
Specific Surface ◽  
Surface Area ◽  
Gas Sensor ◽  
Temperature Stability ◽  
High Sensitivity ◽  
Response Speed ◽  
High Temperature Stability ◽  
The Relationship

To improve the temperature stability, response speed and sensitivity of surface acoustic wave (SAW) gas sensor, the relationship between the sensing region of the resonator for SAW gas sensor and the sensitivity of sensor is studied, a specific resonator with big space topology structure is proposed. A SAW resonator with high temperature stability is investigated from the viewpoint of piezoelectric material, cut type and fabrication process. A nano-wire bundle based SAW gas sensor with big specific-surface-area is proposed.

Effect of Molecular Weight (MW) and End-Groups on the Thermal and Lewis-Acid Catalyzed Decomposition of Fomblin Z-Type Lubricants

2005 ◽  
Author(s):  
Lei Li ◽  
Paul M. Jones ◽  
Alexei G. Merzlikine ◽  
Yiao-Tee Hsia
Keyword(s):  
Molecular Weight ◽  
Lewis Acid ◽  
Elevated Temperatures ◽  
Temperature Stability ◽  
Lewis Acid Site ◽  
High Temperature Stability ◽  
Disk Interface ◽  
End Groups ◽  
Acid Catalyzed ◽  
Fomblin Z

The high-temperature stability of disk lubricants has attracted a lot of interest in recent years because smaller head-media spacing may cause head-media contact and thus a local temperature rise. At elevated temperatures, the lubricant may either evaporate or decompose, leading to the eventual failure of the head-media interface. The decomposition might result from heating and/or may be catalyzed by the presence of a Lewis acid site at the head-disk interface (HDI). In this paper, we study how the chemical structure, namely, molecular weight (MW) and end-groups (see Fig. 1), of disk lubricants will affect the thermal and Lewis-acid catalyzed decomposition of the lubricant.

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