Mechanical Properties and Microstructure of the Newly Developed Steel (Low C 18Cr-11Ni-3Cu-Mo-Nb-B-N) After Aging Treatment

2020 ◽  
Author(s):  
Nao Otaki ◽  
Tomoaki Hamaguchi ◽  
Takahiro Osuki ◽  
Yuhei Suzuki ◽  
Masaki Ueyama ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Vickers Hardness ◽  
Elevated Temperatures ◽  
Rupture Strength ◽  
Aging Treatment ◽  
High Strength ◽  
High Temperature Strength ◽  
Short Term ◽  
Rich Phase

Abstract In petroleum refinery plants, materials with high sensitization resistance are required. 347AP has particularly been developed for such applications and shows good sensitization resistance owing to its low C content. However, further improvement in high temperature strength is required for high temperature operations in complex refineries, such as delayed cokers. Recently, a new austenitic stainless steel (low C 18Cr-11Ni-3Cu-Mo-Nb-B-N, UNS No. S34752) with high sensitization resistance and high strength at elevated temperatures has been developed. In this study, the mechanical properties and microstructures of several aged specimens will be reported. By conducting several aging heat treatments in the range of 550–750 °C for 300–10,000 h on the developed steel, it was revealed that there were only few coarse precipitates that assumed sigma phase even after aging at 750 °C for 10,000 h. This indicates that the newly developed steel has superior phase stability. The developed steel drastically increased its Vickers hardness by short-term aging treatments. Through transmission electron microscopy observations, the fine precipitates of Cu-rich phase were observed dispersedly in the ruptured specimen. Therefore, the increase in Vickers hardness in short-term aging is possibly owing to the dispersed precipitation of Cu-rich phase. There was further increase in Vickers hardness owing to Z phase precipitation; however, the increment was smaller than that caused by Cu-rich phase. The newly developed alloy demonstrated excellent creep rupture strength even in the long-term tests of approximately 30,000 h, which is attributed to these precipitates.

Effect of different fiber types on the mechanical properties of normal and high strength concrete at elevated temperatures

2021 ◽  
Vol 12 (1) ◽  
pp. 30
Author(s):  
Mohamed Amin ◽  
Khaled Abu el-hassan
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
High Strength Concrete ◽  
Elevated Temperatures ◽  
Polypropylene Fiber ◽  
High Strength ◽  
Fiber Types ◽  
Strength Concrete ◽  
Compressive And Flexural Strengths ◽  
Fiber Addition

The effects of the types of fibers on mechanical properties of normal and high strength concrete under high temperature, up to 700 °C, was investigated. Three different- type fiber; "Steel Fiber (SF), Glass Fiber (GF) and Polypropylene Fiber (PPF)" are added into the concretes in five different ratios (0, 0.50, 1.00, 1.50 and 2.0%)of the volume under the following temperatures; 22, 100, 400 and 700°C. The results indicate that all the different types of fibers researched contribute to both the compressive and flexural strengths of concrete under high temperature, however, it is also found that this contribution decreases with an increase in temperature. The flexural strengths and compressive strengths for NSC and HSC mixes at 28 days under high temperature decreases as the temperature increases especially up to 400°C. Also, the best compressive and flexural strengths performance under high temperature was also those of SF. The compressive strength of the concrete incorporating SF was reduced under high temperature only, while the mixes containing PPF and GF were reduced under high temperature or with fiber addition. The optimum fiber addition ratios of the mixes containing PPF and GF are between 0.5-1.0 percent by volume. And for SF, it is 1.5% by the volume.

Changes In The Distribution And Morphology of γ' Precipitate In Neutron Irradiated Pe-16

1976 ◽  
Vol 34 ◽  
pp. 602-603
Author(s):  
P. S. Sklad ◽  
J. Bentley
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Aging Treatment ◽  
Strength Properties ◽  
High Temperature Strength ◽  
Fuel Element Cladding ◽  
Fee Structure ◽  
Solution Treated ◽  
Coherent Precipitate ◽  
Breeder Reactors

Nimonic PE-16 is a γ' hardened, austenitic alloy which has been chosen as a candidate for fuel element cladding and structural component applications in future breeder reactors due to its attractive high temperature strength properties and swelling resistance. The γ' phase is an ordered fee structure of LI2 symmetry having a Ni3(Al, Ti) composition, and is generally found as a finely distributed, spherical, coherent precipitate.Cylindrical (∽6 mm diam x ∽10 mm length) specimens were machined from rod and then solution treated at 1313 K for 2 hr followed by an aging treatment of 2 hr at 1073 K plus 16 hr at 973 K. Specimens were irradiated in the EBR-II at temperatures in the range 650 to 823 K and to fluences in the range 1.2 to 4.0 x 1026 n.m-2 (E >0.1 MeV). Details of the swelling and mechanical properties will be reported elsewhere.

Performance of spent garnet as a sand replacement in high-strength concrete exposed to high temperature

2019 ◽  
Vol 10 (4) ◽  
pp. 468-481 ◽  
Author(s):  
Mariyana Aida Ab Kadir ◽  
Mohammad Iqbal Khiyon ◽  
Abdul Rahman Mohd. Sam ◽  
Ahmad Beng Hong Kueh ◽  
Nor Hasanah Abdul Shukor Lim ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Elevated Temperature ◽  
High Strength Concrete ◽  
Elevated Temperatures ◽  
High Strength ◽  
Concrete Cover ◽  
Content Type ◽  
Concrete Production ◽  
Natural Aggregates

Purpose The purpose of this paper is to examine the mechanical properties, material composition of spent garnet as a sand replacement in high-strength concrete at room and elevated temperatures. Bonding of the concrete containing spent garnet and reinforcing rebar is investigated. Moreover, the optimum thickness of concrete cover subjected to elevated temperatures is investigated. Design/methodology/approach First, the plain spent garnet was physically, chemically and thermally studied. Then, a series of concrete specimens with 0, 20, 40, 60, 80 and 100 per cent of spent garnet were prepared to determine the optimum percentage of spent garnet. Finally, the physical and mechanical behaviours of concrete specimens and effects of cover thickness on steel rebar when subjected to elevated temperature of 200°C, 400°C, 600°C and 800°C for 1 h were studied. It was observed that spent garnet was thermally stable compared to river sand. Findings Mechanical properties were found to be optimal for concrete with 40% spent garnet replacement. Physically, spent garnet concrete changed colour to brown at 400°C, and to whitish grey at 600°C. The residual compressive strength of spent garnet concrete was also found slightly higher than that for control specimens. At various high temperatures, the reduction in ultimate tensile stress for steel bar inside concrete cover of 30 mm was the lowest compared to that of 20 mm. Research limitations/implications Spalling effect it not considered in this study. Practical implications The optimum concrete cover is important issues in reinforced concrete design. This can be used as a guideline by structural designers when using a different type of concrete material in the construction. Social implications Utilization of the waste spent garnet reduces usage of natural aggregates in concrete production and enhances its performance at elevated temperatures. Natural aggregates are normally taken from sand and rock. The new innovation in concrete perhaps can produce light concrete, reduce the cost of concrete production and at the same time also mitigates environmental problems affect from waste material such as minimizing disposal area. Originality/value Utilization of spent garnet in ordinary Portland cement (OPC) concrete at high temperature is a new innovation. It shows that the concrete cover of the concrete element reduced as compared to the OPC concrete. Reduce in weight concrete however the strength of concrete is similar to conventional concrete. This study at elevated temperature has never been performed by any previous researcher.

High-temperature properties of a silicon nitride/boron nitride nanocomposite

2004 ◽  
Vol 19 (5) ◽  
pp. 1432-1438 ◽  
Author(s):  
Takafumi Kusunose ◽  
Rak-Joo Sung ◽  
Tohru Sekino ◽  
Shuji Sakaguchi ◽  
Koichi Niihara
Keyword(s):  
Crystal Structure ◽  
Mechanical Properties ◽  
High Temperature ◽  
Young’S Modulus ◽  
Elevated Temperatures ◽  
Young's Modulus ◽  
High Temperature Strength ◽  
Second Phase ◽  
Structural Ceramics ◽  
High Temperature Mechanical Properties

Hexagonal graphitic BN (h-BN) is interesting as a second phase for high-temperature structural ceramics because it has the same crystal structure as graphite, for which fracture strength and Young’s modulus increase with increased temperature. In this study, high-temperature mechanical properties of Si3N4/BN nanocomposite were evaluated to clarify the effect of fine h-BN particles at elevated temperatures. As a result, we found that high-temperature strength and hardness of the nanocomposite were maintained up to high temperatures; also, its Young’s modulus increased gradually, concomitant with elevated temperatures up to 1400 °C. Finally, these properties were compared with those of monolithic Si3N4 and Si3N4/BN microcomposite.

scholarly journals Micro-Shear Bands and Their Enhancement on High Temperature Strength of Mg-Gd-Y-Zr Alloy

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3262
Author(s):  
Hongchao Xiao ◽  
Zhengjiang Yang ◽  
Jie Li ◽  
Yingchun Wan
Keyword(s):  
Mechanical Properties ◽  
Fracture Behavior ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Shear Bands ◽  
Aging Treatment ◽  
Deformation Mode ◽  
High Temperature Strength ◽  
Subsequent Aging ◽  
Zr Alloy

When Mg-Gd-Y-Zr alloy is cold forged, a large number of nano-micro shear bands are formed inside the grains. It is observed that micro-shear bands hinder the sliding of dislocations, resulting in an increase in tensile strength at elevated temperatures. The subsequent aging treatment further strengthens the alloy. Compared with unforged aged alloys, aged samples with pre-generated micro-shear bands exhibit higher strength at room temperature to 250 °C, but exhibit similar properties at higher temperatures. Microstructure characterization and fracture behavior analysis indicate that the transformation of deformation mode from dislocation sliding to grain boundary activity is mainly due to the change of mechanical properties with temperature. In addition, the alloy precipitates with the aid of dislocations during tension, and exhibits higher strength at 200 °C than that at room temperature.

Lattice Imaging of Grain Boundaries in Ceramics

1977 ◽  
Vol 35 ◽  
pp. 114-115
Author(s):  
D. R. Clarke ◽  
G. Thomas
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Silicon Nitride ◽  
Grain Boundaries ◽  
High Temperature Strength ◽  
Current Interest ◽  
Lattice Imaging ◽  
Special Significance ◽  
Structural Applications ◽  
Refractory Ceramics

Grain boundaries have long held a special significance to ceramicists. In part, this has been because it has been impossible until now to actually observe the boundaries themselves. Just as important, however, is the fact that the grain boundaries and their environs have a determing influence on both the mechanisms by which powder compaction occurs during fabrication, and on the overall mechanical properties of the material. One area where the grain boundary plays a particularly important role is in the high temperature strength of hot-pressed ceramics. This is a subject of current interest as extensive efforts are being made to develop ceramics, such as silicon nitride alloys, for high temperature structural applications. In this presentation we describe how the techniques of lattice fringe imaging have made it possible to study the grain boundaries in a number of refractory ceramics, and illustrate some of the findings.

Phase transformation and layer evolution in molybdenum disilicide-silicon carbide nanolayered coatings

1994 ◽  
Vol 52 ◽  
pp. 538-539
Author(s):  
H. Kung ◽  
T. R. Jervis ◽  
J.-P. Hirvonen ◽  
M. Nastasi ◽  
T. E. Mitchell ◽  
...  
Keyword(s):  
Phase Transformation ◽  
High Temperature ◽  
Oxidation Resistance ◽  
Elevated Temperatures ◽  
Matrix Material ◽  
Molybdenum Disilicide ◽  
High Temperature Strength ◽  
Cross Sectional ◽  
Good Oxidation Resistance ◽  
Structural Applications

MoSi2 is a potential matrix material for high temperature structural composites due to its high melting temperature and good oxidation resistance at elevated temperatures. The two major drawbacksfor structural applications are inadequate high temperature strength and poor low temperature ductility. The search for appropriate composite additions has been the focus of extensive investigations in recent years. The addition of SiC in a nanolayered configuration was shown to exhibit superior oxidation resistance and significant hardness increase through annealing at 500°C. One potential application of MoSi2- SiC multilayers is for high temperature coatings, where structural stability ofthe layering is of major concern. In this study, we have systematically investigated both the evolution of phases and the stability of layers by varying the heat treating conditions.Alternating layers of MoSi2 and SiC were synthesized by DC-magnetron and rf-diode sputtering respectively. Cross-sectional transmission electron microscopy (XTEM) was used to examine three distinct reactions in the specimens when exposed to different annealing conditions: crystallization and phase transformation of MoSi2, crystallization of SiC, and spheroidization of the layer structures.

CARLSON ALLOY C600 and C600 ESR

Alloy Digest ◽  
1994 ◽  
Vol 43 (11) ◽  
Keyword(s):  
Mechanical Properties ◽  
Solid Solution ◽  
Fracture Toughness ◽  
Cold Working ◽  
Elevated Temperatures ◽  
High Strength ◽  
Heat Treating ◽  
Solid Solution Alloy ◽  
Resistance To Oxidation ◽  
Good Workability

Abstract CARLSON ALLOYS C600 AND C600 ESR have excellent mechanical properties from sub-zero to elevated temperatures with excellent resistance to oxidation at high temperatures. It is a solid-solution alloy that can be hardened only by cold working. High strength at temperature is combined with good workability. 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, and machining. Filing Code: Ni-470. Producer or source: G.O. Carlson Inc.

BERYLCO NICKEL ALLOY 440

Alloy Digest ◽  
1975 ◽  
Vol 24 (9) ◽  
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Nickel Alloy ◽  
High Strength ◽  
Heat Treating ◽  
Electronic Components ◽  
High Temperature Mechanical Properties ◽  
Temperature Performance ◽  
Solution Treated ◽  
Complex Shapes

Abstract BERYLCO NICKEL ALLOY 440 is an age-hardenable nickel-beryllium-titanium alloy that offers high strength, excellent spring properties outstanding formability, good high-temperature mechanical properties, and resistance to corrosion and fatigue. Complex shapes can be produced in the solution-treated (soft) condition and then aged to a minimum tensile strength of 215,500 psi. It is used for mechanical and electrical/electronic components in the temperature range -320 to 800 F. 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 and corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: Ni-94. Producer or source: Kawecki Berylco Industries Inc.. Originally published September 1964, revised September 1975.

CARPENTER L-605 ALLOY

Alloy Digest ◽  
1987 ◽  
Vol 36 (8) ◽  
Keyword(s):  
Corrosion Resistance ◽  
High Temperature ◽  
Elevated Temperatures ◽  
Base Alloy ◽  
High Strength ◽  
Heat Treating ◽  
Temperature Performance ◽  
Cobalt Base Alloy ◽  
Cobalt Base ◽  
Oxidation And Corrosion

Abstract CARPENTER L-605 alloy is a nonmagnetic cobalt-base alloy that has good oxidation and corrosion resistance and high strength at elevated temperatures. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as 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: Co-81. Producer or source: Carpenter.

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