Thermal stability evaluation of microstructures and mechanical properties of tungsten vanadium alloys

2014 ◽  
Vol 28 (26) ◽  
pp. 1450207 ◽  
Author(s):  
Kameel Arshad ◽  
Ming-Yue Zhao ◽  
Yue Yuan ◽  
Ying Zhang ◽  
Zhang-Jian Zhou ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Thermal Stability ◽  
Flexural Strength ◽  
High Heat ◽  
High Heat Flux ◽  
Plasma Sintering ◽  
Microstructures And Mechanical Properties ◽  
The Impact ◽  
Thermal Stability Of

The thermal stability is important for tungsten based alloys as plasma facing materials to survive against high heat flux in fusion reactors. In this work, the thermal stability of W-5%V alloy fabricated following a powder metallurgy route by spark plasma sintering technique has been studied. To investigate the impact of temperature on the mechanical properties and microstructures, the alloy was subjected to heat treatment for 2 h over the temperature range 900–1500°C in a pure argon furnace. The micro-hardness values of the heat treated alloys were highly stable as compared to pure tungsten. A slight decrease flexural strength was observed with increasing annealing temperature. The maximum change flexural strength at the highest treated temperature was noted about 14% lower. The morphology analyses of the crack surfaces by scanning electron microscopy did not identify a drastic change in tungsten grain size, after heat treatment. The results indicate that the addition of vanadium in tungsten improves the overall thermal stability of microstructures and mechanical properties.

scholarly journals Optimization of the Solidification Method of High-Level Waste for Increasing the Thermal Stability of the Magnesium Potassium Phosphate Compound

Energies ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3789
Author(s):  
Svetlana A. Kulikova ◽  
Sergey S. Danilov ◽  
Kseniya Yu. Belova ◽  
Anastasiya A. Rodionova ◽  
Sergey E. Vinokurov
Keyword(s):  
Heat Treatment ◽  
Thermal Stability ◽  
Compressive Strength ◽  
Potassium Phosphate ◽  
Treatment Temperature ◽  
High Level Waste ◽  
Leaching Rate ◽  
High Level ◽  
The Impact ◽  
Thermal Stability Of

The key task in the solidification of high-level waste (HLW) into a magnesium potassium phosphate (MPP) compound is the immobilization of mobile cesium isotopes, the activity of which provides the main contribution to the total HLW activity. In addition, the obtained compound containing heat-generating radionuclides can be significantly heated, which increases the necessity of its thermal stability. The current work is aimed at assessing the impact of various methodological approaches to HLW solidification on the thermal stability of the MPP compound, which is evaluated by the mechanical strength of the compound and its resistance to cesium leaching. High-salt surrogate HLW solution (S-HLW) used in the investigation was prepared for solidification by adding sorbents of various types binding at least 93% of 137Cs: ferrocyanide K-Ni (FKN), natural zeolite (NZ), synthetic zeolite Na-mordenite (MOR), and silicotungstic acid (STA). Prepared S-HLW was solidified into the MPP compound. Wollastonite (W) and NZ as fillers were added to the compound composition in the case of using FKN and STA, respectively. It was found that heat treatment up to 450 °C of the compound containing FKN and W (MPP-FKN-W) almost did not affect its compressive strength (about 12–19 МPa), and it led to a decrease of high compressive strength (40–50 MPa) of the compounds containing NZ, MOR, and STA (MPP-NZ, MPP-MOR, and MPP-STA-NZ, respectively) by an average of 2–3 times. It was shown that the differential leaching rate of 137Cs on the 28th day from MPP-FKN-W after heating to 250 °C was 5.3 × 10−6 g/(cm2∙day), however, at a higher temperature, it increased by 20 and more times. The differential leaching rate of 137Cs from MPP-NZ, MPP-MOR, and MPP-STA-NZ had values of (2.9–11) × 10−5 g/(cm2∙day), while the dependence on the heat treatment temperature of the compound was negligible.

scholarly journals Rigid Polyurethane Foams Reinforced with POSS-Impregnated Sugar Beet Pulp Filler

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5493
Author(s):  
Anna Strąkowska ◽  
Sylwia Członka ◽  
Agnė Kairytė
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Sugar Beet ◽  
Sugar Beet Pulp ◽  
Polyhedral Oligomeric Silsesquioxanes ◽  
Limiting Oxygen Index ◽  
Composite Foams ◽  
Beet Pulp ◽  
The Impact ◽  
Thermal Stability Of

Rigid polyurethane (PUR) foams were reinforced with sugar beet pulp (BP) impregnated with Aminopropylisobutyl-polyhedral oligomeric silsesquioxanes (APIB-POSS). BP filler was incorporated into PUR at different percentages—1, 2, and 5 wt.%. The impact of BP filler on morphology features, mechanical performances, and thermal stability of PUR was examined. The results revealed that the greatest improvement in physico-mechanical properties was observed at lower concentrations (1 and 2 wt.%) of BP filler. For example, when compared with neat PUR foams, the addition of 2 wt.% of BP resulted in the formation of PUR composite foams with increased compressive strength (~12%), greater flexural strength (~12%), and better impact strength (~6%). The results of thermogravimetric analysis (TGA) revealed that, due to the good thermal stability of POSS-impregnated BP filler, the reinforced PUR composite foams were characterized by better thermal stability—for example, by increasing the content of BP filler up to 5 wt.%, the mass residue measured at 600 °C increased from 29.0 to 31.9%. Moreover, the addition of each amount of filler resulted in the improvement of fire resistance of PUR composite foams, which was determined by measuring the value of heat peak release (pHRR), total heat release (THR), total smoke release (TSR), limiting oxygen index (LOI), and the amount of carbon monoxide (CO) and carbon dioxide (CO2) released during the combustion. The greatest improvement was observed for PUR composite foams with 2 wt.% of BP filler. The results presented in the current study indicate that the addition of a proper amount of POSS-impregnated BP filler may be an effective approach to the synthesis of PUR composites with improved physico-mechanical properties. Due to the outstanding properties of PUR composite foams reinforced with POSS-impregnated BP, such developed materials may be successfully used as thermal insulation materials in the building and construction industry.

Thermal, mechanical, and dielectric properties of epoxy resin modified using carboxyl-terminated polybutadiene liquid rubber

2016 ◽  
Vol 49 (4) ◽  
pp. 281-297 ◽  
Author(s):  
Lina Dong ◽  
Wenying Zhou ◽  
Xuezhen Sui ◽  
Zijun Wang ◽  
Peng Wu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Dissipation Factor ◽  
Wide Frequency Range ◽  
Carboxyl Groups ◽  
Frequency Range ◽  
Two Phase ◽  
Liquid Rubber ◽  
The Impact ◽  
Thermal Stability Of

Epoxy (Ep) resin modified with carboxyl-terminated polybutadiene (CTPB) liquid rubber was investigated in this study. Fourier transform infrared verified the chemical reactions between oxirane ring of Ep and carboxyl groups of CTPB using benzyldimethylamine as a catalyst. The decrease of the thermal stability could be due to the lower thermal stability of CTPB compared with that of pure Ep. The mechanical results showed that CTPB-modified Ep was superior to that of the pure Ep, and the best overall mechanical properties were normally achieved with 20 phr of CTPB content. The impact strength of the system containing 20 phr CTPB increased by 193% due to the two-phase nature of the system. The dielectric constant and dissipation factor of the modified Ep obviously declined with the CTPB content compared with pure Ep, for instance, the dissipation factor remained less than 0.02 in wide frequency range.

scholarly journals Mechanical properties of phase-pure bulk Ta4AlC3 prepared by spark plasma sintering and subsequent heat treatment

2021 ◽  
Vol 15 (3) ◽  
pp. 211-218
Author(s):  
Guobing Ying ◽  
Cong Hu ◽  
Lu Liu ◽  
Cheng Sun ◽  
Dong Wen ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Fracture Toughness ◽  
Flexural Strength ◽  
Spark Plasma Sintering ◽  
Treatment Time ◽  
Raw Materials ◽  
Subsequent Heat Treatment ◽  
Plasma Sintering ◽  
Spark Plasma

High-purity and bulk Ta4AlC3 ceramics were successfully fabricated by spark plasma sintering (SPS) and subsequent heat treatment, using the raw materials including TaC and Ta2AlC powders. These raw materials were first synthesized by self-propagation high temperature synthesis from elements tantalum, aluminium and carbon black powders, followed by pressure-less sintering. The as-fabricated bulk Ta4AlC3 was relatively stable when subjected to heat treatment at elevated temperature of 1500?C. Moreover, prolonging the heat treatment time resulted in bigger grain sizes and higher densities of the Ta4AlC3. The flexural strength and the fracture toughness of the Ta4AlC3 fabricated by SPS were found to be 411MPa and 7.11MPa?m1/2, respectively. After the heat treatment at 1500?C for 8 h, the flexural strength and the fracture toughness of the Ta4AlC3 could reach 709MPa and 9.23MPa?m1/2, respectively. The special structural characteristics of the ternary ceramics and the increase of density after the heat treatment are the main reasons for the variation in mechanical properties of ternary ceramics.

scholarly journals Tailoring the Glass Composition to Increase the Thermal Stability without Impacting the Crystallization Behavior of Oxyfluorophosphate Glass

Ceramics ◽  
2021 ◽  
Vol 4 (2) ◽  
pp. 148-159
Author(s):  
Nirajan Ojha ◽  
Iuliia Dmitrieva ◽  
Wilfried Blanc ◽  
Laeticia Petit
Keyword(s):  
Heat Treatment ◽  
Thermal Stability ◽  
Glass Ceramic ◽  
Glass Composition ◽  
Glass Ceramics ◽  
Glass Network ◽  
Thermally Stable ◽  
Heat Treated ◽  
The Impact ◽  
Thermal Stability Of

Even though the (75 NaPO3-25 CaF2) (in mol%) glass can be heat-treated into transparent glass-ceramic with Er3+ doped CaF2 crystals precipitating in the volume of the glass during heat-treatment, this glass was found to be a poor glass former, limiting its use as upconverter under 975 nm pumping. In this study, the impact of the glass composition on the thermal, optical and structural properties of the glass was investigated in order to understand how the glass composition can be tailored for the development of thermally stable upconverter glass-based material. The addition of MgO, Fe2O3 and Al2O3 in the NaPO3-CaF2 glass system increases the thermal stability of glass due to the depolymerization of the glass network. However, the changes in the glass composition also impacted on the nucleation and growth process. Indeed, CaF2 and other crystals were found in the newly developed glasses after heat-treatment leading to glass-ceramics with lower intensity of upconversion than the (75 NaPO3-25 CaF2) glass-ceramic used as a reference. Glasses were also prepared with different concentrations of Er2O3 and ErF3. These glasses were found to be promising as not only are they thermally stable, but they also exhibit green and red emission with high intensity under 975 nm pumping due to Er3+ clustering.

Study on the Morphology, Mechanical, Thermal Stability Properties of Poly(Lactic-Acid)/Poly(Ether-Block-Amide) Blends Prepared by Triple-Single Screw Extruder

2018 ◽  
Vol 783 ◽  
pp. 51-55
Author(s):  
Bin Xue ◽  
He Zhi He ◽  
Bi Da Liu ◽  
Feng Xue ◽  
Zhi Wen Zhu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Phase Interface ◽  
Poly Lactic Acid ◽  
Screw Extruder ◽  
Two Phase ◽  
Single Screw ◽  
Single Screw Extruder ◽  
The Impact ◽  
Thermal Stability Of

In this work, PLA /PEBA blends with the addition of different PEBA contents were prepared via self-made Triple-Single Screw Extruder, the phase morphology, mechanical properties thermal stability of PLA /PEBA blends with PEBA content were investigated. For the pure PLA, the tensile strength decreased, while the elongation at break and the impact strength increased significantly with addition of 15% PEBA. The which were improved nearly 23 and 5 times. The results illustrate that the soft component PEBA was beneficial to improve the tensile ductility and the toughness of PLA. SEM measurements indicate the PEBA and PLA intertwined with each other, two phases interface bond tightly, improving the compatibility of the blends when PEBA content is not more than 15 wt%, with further increasing PEBA, the two-phase interface appears and decreases the interfacial adhesion, resulting in the poor mechanical properties of blends.TG results reveal that thermal stability of PLA/PEBA blends was improved.

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