scholarly journals The Impact of Interphase Precipitation on the Mechanical Behavior of Fire-Resistant Steels at an Elevated Temperature

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4294
Author(s):  
Jinghua Cong ◽  
Jiangwen Li ◽  
Jiajie Fan ◽  
Pengcheng Liu ◽  
Raja Devesh Kumar Misra ◽  
...  
Keyword(s):  
Elevated Temperature ◽  
Elevated Temperatures ◽  
Volume Fraction ◽  
Isothermal Holding ◽  
High Strength ◽  
Controlled Rolling ◽  
Thermally Stable ◽  
Laminar Cooling ◽  
Interphase Precipitation ◽  
The Impact

In this study, we address the challenge of obtaining high strength at ambient and elevated temperatures in fire-resistant Ti–Mo–V steel with ferrite microstructures through thermo-mechanical controlled processing (TMCP). Thermally stable interphase precipitation of (Ti, Mo, V)C was an important criterion for retaining strength at elevated temperatures. Electron microscopy indicated that interphase precipitation occurred during continuous cooling after controlled rolling, where the volume fraction of interphase precipitation was controlled by the laminar cooling temperature. The interphase precipitation of MC carbides with an NaCl-type crystal structure indicated a Baker–Nutting (B–N) orientation relationship with ferrite. When the steel was isothermally held at 600 °C for up to 3 h, interphase precipitation occurred during TMCP with high thermal stability. At the same time, some random precipitation took place during isothermal holding. The interphase precipitation increased the elastic modulus of the experimental steels at an elevated temperature. It is proposed that fire-resistant steel with thermally stable interphase precipitation is preferred, which enhances precipitation strengthening and dislocation strengthening at elevated temperatures.

scholarly journals R-BPMV-Mediated Resistance to Bean pod mottle virus in Phaseolus vulgaris L. Is Heat-Stable but Elevated Temperatures Boost Viral Infection in Susceptible Genotypes

Viruses ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1239
Author(s):  
Chouaïb Meziadi ◽  
Julie Lintz ◽  
Masoud Naderpour ◽  
Charlotte Gautier ◽  
Sophie Blanchet ◽  
...  
Keyword(s):  
Elevated Temperature ◽  
Phaseolus Vulgaris ◽  
Elevated Temperatures ◽  
Heat Waves ◽  
Dominant Gene ◽  
Atmospheric Temperature ◽  
Mottle Virus ◽  
Bean Pod Mottle Virus ◽  
Heat Stable ◽  
The Impact

In the context of climate change, elevated temperature is a major concern due to the impact on plant–pathogen interactions. Although atmospheric temperature is predicted to increase in the next century, heat waves during summer seasons have already become a current problem. Elevated temperatures strongly influence plant–virus interactions, the most drastic effect being a breakdown of plant viral resistance conferred by some major resistance genes. In this work, we focused on the R-BPMV gene, a major resistance gene against Bean pod mottle virus in Phaseolus vulgaris. We inoculated different BPMV constructs in order to study the behavior of the R-BPMV-mediated resistance at normal (20 °C) and elevated temperatures (constant 25, 30, and 35 °C). Our results show that R-BPMV mediates a temperature-dependent phenotype of resistance from hypersensitive reaction at 20 °C to chlorotic lesions at 35 °C in the resistant genotype BAT93. BPMV is detected in inoculated leaves but not in systemic ones, suggesting that the resistance remains heat-stable up to 35 °C. R-BPMV segregates as an incompletely dominant gene in an F2 population. We also investigated the impact of elevated temperature on BPMV infection in susceptible genotypes, and our results reveal that elevated temperatures boost BPMV infection both locally and systemically in susceptible genotypes.

scholarly journals Experiment on Foreign Object Damage of Gas Turbine-Grade Silicon Nitride Ceramic

1998 ◽  
Author(s):  
Hiro Yoshida ◽  
Takashi Nakashima ◽  
Makoto Yoshida ◽  
Yasushi Hara ◽  
Toru Shimamori
Keyword(s):  
Elevated Temperature ◽  
Silicon Nitride ◽  
Elevated Temperatures ◽  
Tensile Load ◽  
Strength Degradation ◽  
Spall Fracture ◽  
Silicon Nitride Ceramic ◽  
Impact Tests ◽  
The Impact ◽  
Bending Fracture

A new high quality turbine system using monolithic silicon-nitride ceramic is under development. In this study particle impact tests of the silicon-nitride have been tried at room and elevated temperatures with and without tensile load, which simulates centrifugal force of blade rotation. In the experiment 1 mm diameter particle is impacted at velocities up to 900 m s−1. In this paper, critical velocities for bending fracture and Hertzian cracks are examined. Moreover, strength degradation at elevated temperature and spall fracture of the blade are discussed. The main results are: 1) The bending fracture mode critical impact velocity for soft particles is higher than that for hard particles. 2)The impact parameter ϕ for initiation of Hertzian cracks ranges 1.08×10−5 – 1.56×10−5 for the materials tested. 3)Strength degradation at elevated temperature was clearly observed. 4) In the impact tests on blades spall fracture, which was caused by interaction of stress waves, appeared.

Microstructure and Tensile Properties of TRIP-Aided Steel Sheet Subjected to Hot-Rolling and Austempering

2021 ◽  
Vol 1016 ◽  
pp. 732-737
Author(s):  
Junya Kobayashi ◽  
Hiroto Sawayama ◽  
Naoya Kakefuda ◽  
Goroh Itoh ◽  
Shigeru Kuraoto ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Hot Rolling ◽  
Manufacturing Process ◽  
Retained Austenite ◽  
Volume Fraction ◽  
Isothermal Holding ◽  
High Strength ◽  
Isothermal Transformation ◽  
Transformation Process ◽  
Steel Sheets

Various high strength steel sheets for weight reduction and safety improvement of vehicles have been developed. TRIP-aided steel with transformation induced plasticity of the retained austenite has high strength and ductility. Conventional TRIP-aided steels are subjected to austempering process after austenitizing. Generally, elongation and formability of TRIP-aided steel are improved by finely dispersed retained austenite in BCC phase matrix. The finely dispersed retained austenite and grain refinement of TRIP-aided steel can be achieved by hot rolling with heat treatment. Therefore, the improvement of mechanical properties of TRIP-aided steel is expected from the manufacturing process with hot rolling and then isothermal transformation process. In this study, thermomechanical heat treatment is performed by combining hot rolling and isothermal holding as the manufacturing process of TRIP-aided steel sheets. The complex phase matrix is obtained by hot rolling and then isothermal holding. Although the hardness of the hot rolled and isothermal held TRIP-aided steel is decreased, the volume fraction of retained austenite is increased.

Elevated Temperature Properties of Maraging Steel Plates and Welds

1971 ◽  
Vol 93 (2) ◽  
pp. 218-224
Author(s):  
N. Kenyon ◽  
E. P. Sadowski ◽  
P. P. Hydrean
Keyword(s):  
Elevated Temperature ◽  
Maraging Steel ◽  
Elevated Temperatures ◽  
High Strength Steels ◽  
High Strength ◽  
Steel Plates ◽  
Maraging Steels ◽  
Gas Tungsten Arc ◽  
Temperature Exposure ◽  
Rupture Behavior

The creep rupture behavior, and the effects of elevated temperature exposure in air and hydrogen on the subsequent room temperature properties of a 12 percent Ni-5 percent Cr-3 percent Mo maraging steel are described. Tests have been made on several heats of plate and on gas tungsten-arc, gas metal-arc, and electroslag welds. On the basis of the results obtained, maraging steels offer promise as high-strength steels for service at elevated temperatures.

scholarly journals Study on Tensile Properties of CFRP Plates under Elevated Temperature Exposure

Materials ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 1995 ◽  
Author(s):  
Yongxin Yang ◽  
Yanju Jiang ◽  
Hongjun Liang ◽  
Xiaosan Yin ◽  
Yue Huang
Keyword(s):  
Tensile Strength ◽  
Elastic Modulus ◽  
Elevated Temperature ◽  
Tensile Properties ◽  
Failure Mode ◽  
Elevated Temperatures ◽  
Strain Curve ◽  
Effect Of Temperature ◽  
Temperature Exposure ◽  
The Impact

Elevated temperature exposure has a negative effect on the performance of the matrix resin in Carbon Fiber Reinforced Plastics (CFRP) plates, whereas limited quantitative research focuses on the deteriorations. Therefore, 30 CFRP specimens were designed and tested under elevated temperatures (10, 30, 50, 70, and 90 °C) to explore the degradations in tensile properties. The effect of temperature on the failure mode, stress-strain curve, tensile strength, elastic modulus and elongation of CFRP plates were investigated. The results showed that elevated temperature exposure significantly changed the failure characteristics. When the exposed temperature increased from 10 °C to 90 °C, the failure mode changed from the global factures in the whole CFRP plate to the successive fractures in carbon fibers. Moreover, with temperatures increasing, tensile strength and elongation of CFRP plates decreases gradually while the elastic modulus shows negligible change. Finally, the results of One-Way Analysis of Variance (ANOVA) show that the degradation of the tensile strength of CFRP plates was due to the impact of elevated temperature exposure, rather than the test error.

scholarly journals Rheological and Mechanical Properties of Silica/Nitrile Butadiene Rubber Vulcanizates with Eco-Friendly Ionic Liquid

Polymers ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 2763
Author(s):  
Munir Hussain ◽  
Sohail Yasin ◽  
Hafeezullah Memon ◽  
Zhiyun Li ◽  
Xinpeng Fan ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Volume Fraction ◽  
High Strength ◽  
Crosslinking Density ◽  
Mechanical And Thermal Properties ◽  
Butadiene Rubber ◽  
Transmission Electron ◽  
The Matrix ◽  
Silica Dispersion ◽  
The Impact

In this paper we designed greener rubber nanocomposites exhibiting high crosslinking density, and excellent mechanical and thermal properties, with a potential application in technical fields including high-strength and heat-resistance products. Herein 1-ethyl-3-methylimidazolium acetate ([EMIM]OAc) ionic liquid was combined with silane coupling agent to formulate the nanocomposites. The impact of [EMIM]OAc on silica dispersion in a nitrile rubber (NBR) matrix was investigated by a transmission electron microscope and scanning electron microscopy. The combined use of the ionic liquid and silane in an NBR/silica system facilitates the homogeneous dispersion of the silica volume fraction (φ) from 0.041 to 0.177 and enhances crosslinking density of the matrix up to three-fold in comparison with neat NBR, and also it is beneficial for solving the risks of alcohol emission and ignition during the rubber manufacturing. The introduction of ionic liquid greatly improves the mechanical strength (9.7 MPa) with respect to neat NBR vulcanizate, especially at high temperatures e.g., 100 °C. Furthermore, it impacts on rheological behaviors of the nanocomposites and tends to reduce energy dissipation for the vulcanizates under large amplitude dynamic shear deformation.

scholarly journals Faster Removal of 2-Phosphoglycolate through Photorespiration Improves Abiotic Stress Tolerance of Arabidopsis

Plants ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 563 ◽  
Author(s):  
Stefan Timm ◽  
Franziska Woitschach ◽  
Carolin Heise ◽  
Martin Hagemann ◽  
Hermann Bauwe
Keyword(s):  
Abiotic Stress ◽  
Elevated Temperature ◽  
Elevated Temperatures ◽  
Soluble Sugar ◽  
Carbon Assimilation ◽  
High Light ◽  
Starch Accumulation ◽  
Wild Type ◽  
Transgenic Lines ◽  
The Impact

Photorespiration metabolizes 2-phosphoglyolate (2-PG) to avoid inhibition of carbon assimilation and allocation. In addition to 2-PG removal, photorespiration has been shown to play a role in stress protection. Here, we studied the impact of faster 2-PG degradation through overexpression of 2-PG phosphatase (PGLP) on the abiotic stress-response of Arabidopsis thaliana (Arabidopsis). Two transgenic lines and the wild type were subjected to short-time high light and elevated temperature stress during gas exchange measurements. Furthermore, the same lines were exposed to long-term water shortage and elevated temperature stresses. Faster 2-PG degradation allowed maintenance of photosynthesis at combined light and temperatures stress and under water-limiting conditions. The PGLP-overexpressing lines also showed higher photosynthesis compared to the wild type if grown in high temperatures, which also led to increased starch accumulation and shifts in soluble sugar contents. However, only minor effects were detected on amino and organic acid levels. The wild type responded to elevated temperatures with elevated mRNA and protein levels of photorespiratory enzymes, while the transgenic lines displayed only minor changes. Collectively, these results strengthen our previous hypothesis that a faster photorespiratory metabolism improves tolerance against unfavorable environmental conditions, such as high light intensity and temperature as well as drought. In case of PGLP, the likely mechanism is alleviation of inhibitory feedback of 2-PG onto the Calvin–Benson cycle, facilitating carbon assimilation and accumulation of transitory starch.

Isothermal Aging Effects on the Thermal reliability Performance of Lead-Free Solder Joints

2012 ◽  
Vol 2012 (1) ◽  
pp. 000801-000808 ◽  
Author(s):  
Jiawei Zhang ◽  
Zhou Hai ◽  
Sivasubramanian Thirugnanasambandam ◽  
John L. Evans ◽  
M. J. Bozack
Keyword(s):  
Elevated Temperature ◽  
Isothermal Aging ◽  
Elevated Temperatures ◽  
Solder Joints ◽  
Bulk Solder ◽  
Lead Free ◽  
Aging Effects ◽  
Thermal Reliability ◽  
Free Solder ◽  
The Impact

Electronics assemblies containing solder joints are often exposed to elevated temperatures for prolonged periods of time. The time-at-temperature stress impacts the overall package reliability of the assembled circuitry due to evolving materials, microstructural, and mechanical properties. It is especially important to understand the impact of isothermal aging on the long term behavior of lead (Pb)-free solder joints which operate in harsh environments. In this study, we have explored the effects of elevated temperature isothermal aging on the reliability of Sn-Ag-Cu (SAC) assemblies on board level packages. As the isothermal aging temperature increases, the Weybull characteristic lifetime for SAC 105 and 305 solder joints is drastically reduced compared to Sn-37Pb.In parallel mechanical studies on bulk solder specimens, the creep rate for SAC105, 305 rapidly increases with aging. A full test matrix with varying aging temperatures and solder alloys was considered. Package sizes ranged from 19mm, 0.8mm pitch ball grid arrays (BGAs) to 5mm, 0.4mm pitch μBGAs. The test structures were built on three different board finishes (ImSn, ImAg and SnPb). Storage condition temperatures were 25°C, 55°C, 85°C and 125°C with aging over time periods of 0, 6, and 12 months. Subsequently, the specimens were thermally cycled from −40°C to 125°C with 15 min dwell times at the high temperature. It was found that the thermal performance of lead-free fine-pitch packages significantly degrades up to 55–60% after aging at elevated temperature. The dominant failure mode can be associated with the growth of Cu6Sn5 intermetallic compounds (IMC) during the aging, particularly on the pad side.

High Temperature Oxidation Protection of Multi-Phase Mo-Containing TiAl-Alloys by the Fluorine Effect

2012 ◽  
Vol 1516 ◽  
pp. 95-100 ◽  
Author(s):  
Alexander Donchev ◽  
Raluca Pflumm ◽  
Svea Mayer ◽  
Helmut Clemens ◽  
Michael Schütze
Keyword(s):  
High Temperature ◽  
Oxidation Resistance ◽  
Titanium Aluminides ◽  
Elevated Temperatures ◽  
Volume Fraction ◽  
Temperature Oxidation ◽  
Tial Alloys ◽  
Β Phase ◽  
Multi Phase ◽  
The Impact

ABSTRACTIntermetallic titanium aluminides are potential materials for application in high temperature components. In particular, alloys solidifying via the β-phase are of great interest because they possess a significant volume fraction of the disordered body-centered cubic β-phase at elevated temperatures ensuring good processing characteristics during hot-working. Nevertheless, their practical use at temperatures as high as 800°C requires improvements of the oxidation resistance. This paper reports on the fluorine effect on a multi-phase TiAl-alloy in the cast and hot-isostatically pressed condition at 800°C in air. The behavior of the so-called TNM material (Ti-43.5Al-4Nb-1Mo-0.1B, in at %) was compared with that of two other TiAl-alloys which are Nb-free and contain different amounts of Mo (3 and 7 at%, respectively). The oxidation resistance of the fluorine treated samples was significantly improved compared to the untreated samples. After fluorine treatment all alloys exhibit slow alumina kinetics indicating a positive fluorine effect. Results of isothermal and thermocyclic oxidation tests at 800°C in air are presented and discussed in the view of composition and microstructure of the TiAl-alloys investigated, along with the impact of the fluorine effect on the oxidation resistance of these materials.

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