Preparation and Properties of SiC Fibers Containing Yttrium and Aluminum

2008 ◽  
Vol 368-372 ◽  
pp. 827-830 ◽  
Author(s):  
Da Xiang Yang ◽  
Yong Cai Song
Keyword(s):  
Heat Treatment ◽  
Tensile Strength ◽  
Oxygen Content ◽  
Sintering Temperature ◽  
Chemical Vapor ◽  
Treatment Temperature ◽  
Sintering Process ◽  
Dispersion Strengthening ◽  
Sic Fibers ◽  
Different Temperatures

SiC fibers containing Y and Al were prepared by sintering the amorphous KD-Y fibers at different temperatures from 1200 to 1800 °C. The tensile strength of fibers increases when the sintering temperature increases from 1200 to 1400 °C due to the dispersion strengthening of β-SiC microcrystal and decreases to the lowest point when being sintered at 1600 °C, then rose again with the further increase of temperature to 1800 °C. The tensile strength reached to 2.15 GPa. The oxygen content of KD-Y fibers determined the properties of the sintered SiC fibers and sintering process. Through chemical vapor curing (CVC), the oxygen content was controlled below 7.0 wt% and the tensile strength of KD-Y fibers reached to 3.08 GPa. Further-more, the sintering process of KD-Y fibers was discussed and the grain size of β-SiC grew up with the heat treatment temperature.

scholarly journals Grain Refinement and Improved Mechanical Properties of EUROFER97 by Thermo-Mechanical Treatments

2021 ◽  
Vol 11 (22) ◽  
pp. 10598
Author(s):  
Giulia Stornelli ◽  
Andrea Di Schino ◽  
Silvia Mancini ◽  
Roberto Montanari ◽  
Claudio Testani ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Tensile Strength ◽  
Heat Treatments ◽  
Treatment Temperature ◽  
Steel Plates ◽  
Experimental Campaign ◽  
Different Temperatures ◽  
Fusion Applications ◽  
Cold Rolled

EUROFER97 steel plates for nuclear fusion applications are usually manufactured by hot rolling and subsequent heat treatments: (1) austenitization at 980 °C for 30 min, (2) rapid cooling and (3) tempering at 760 °C for 90 min. An extended experimental campaign was carried out with the scope of improving the strength of the steel without a loss of ductility. Forty groups of samples were prepared by combining cold rolling with five cold reduction ratios (20, 40, 50, 60 and 80%) and heat treatments at eight different temperatures in the range 400–750 °C (steps of 50 °C). This work reports preliminary results regarding the microstructure and mechanical properties of all the cold-rolled samples and the effects of heat treatments on the samples deformed with the greater CR ratio (80%). The strength of deformed samples decreased as heat treatment temperature increased and the change was more pronounced in the samples cold-rolled with greater CR ratios. After heat treatments at temperature up to 600 °C yield stress (YS) and ultimate tensile strength (UTS) of samples deformed with CR ratio of 80% were significantly larger than those of standard EUROFER97 but ductility was lower. On the contrary, the treatment at 650 °C produced a fully recrystallized structure with sub-micrometric grains which guarantees higher strength and comparable ductility. The work demonstrated that EUROFER97 steel can be strengthened without compromising its ductility; the most effective process parameters will be identified by completing the analyses on all the prepared samples.

Effect of isothermal heat treatment on crystallinity, tensile strength and failure mode of CF/PPS laminate

2020 ◽  
pp. 095400832096984
Author(s):  
Yankuan Liu ◽  
Xuelin Zhou ◽  
Zhiping Wang
Keyword(s):  
Heat Treatment ◽  
Tensile Strength ◽  
Failure Mode ◽  
Failure Modes ◽  
Treatment Temperature ◽  
Isothermal Heat Treatment ◽  
Fiber Extraction ◽  
A Value ◽  
Different Temperatures ◽  
Laser Confocal Microscope

The present work concentrates on the crystallinity, tensile strength and failure mode of CF/PPS laminate subjected to isothermal heat treatment of different temperatures and time periods. Results show that in the range of 100–210°C and 1–3 hours, with the increase of heat treatment temperature and time, both crystallinity and tensile strength of CF/PPS laminate increase firstly then decrease. Under the condition of 150°C-2 hours treatment, the CF/PPS has the optimal crystallinity level of 65.3% and the optimal tensile strength with a value of 718.2 MPa. Compared with the as-received specimen without heat treatment, the crystallinity and tensile strength have been increased by 46.4% and 15.3%, respectively. A laser confocal microscope has been used to observe and analyze the fracture morphologies of the specimens, results show that the failure modes of the specimens under conditions of 100°C and 150°C isothermal heat treatment are fiber extraction and fiber breakage, respectively, and both are AGM, while that of 210°C is debonding and delamination, which is DGM.

scholarly journals Effects of Different Solid Solution Temperatures on Microstructure and Mechanical Properties of the AA7075 Alloy After T6 Heat Treatment

2019 ◽  
Vol 38 (2019) ◽  
pp. 892-896 ◽  
Author(s):  
Süleyman Tekeli ◽  
Ijlal Simsek ◽  
Dogan Simsek ◽  
Dursun Ozyurek
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Solid Solution ◽  
Tensile Strength ◽  
Tensile Tests ◽  
Solution Temperature ◽  
T6 Heat Treatment ◽  
Microstructure And Mechanical Properties ◽  
Different Temperatures

AbstractIn this study, the effect of solid solution temperature on microstructure and mechanical properties of the AA7075 alloy after T6 heat treatment was investigated. Following solid solution at five different temperatures for 2 hours, the AA7075 alloy was quenched and then artificially aged at 120∘C for 24 hours. Hardness measurements, microstructure examinations (SEM+EDS, XRD) and tensile tests were carried out for the alloys. The results showed that the increased solid solution temperature led to formation of precipitates in the microstructures and thus caused higher hardness and tensile strength.

scholarly journals Improving Spinnability of Hyper-coal Derived Spinnable Pitch through the Hydrogenation with 1, 2, 3, 4-tetrahydroquinoline

2018 ◽  
Author(s):  
Jianxiao Yang ◽  
Wei Wu ◽  
Xiaxiang Zhang ◽  
Kui Shi ◽  
Xuanke Li ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Heat Treatment ◽  
Tensile Strength ◽  
Carbon Fiber ◽  
Oxygen Content ◽  
Softening Point

The proper hydrogenation of Hyper-coal (HPC) using 1, 2, 3, 4-tetrahydroquinoline (THQ) was able to decrease the oxygen content and adjust the molecular structure of HPC for preparing the spinnable pitch with high softening point (SP). The spinnable pitch prepared from the THQ-soluble (QS) fraction of HPC as a precursor consisted more naphthenic carbon groups than that prepared from the 1-methylnaphthalene (1-MN) soluble (MNS) fraction of HPC. The HPC-QS derived pitch showed excellent spinnability even the SP of 260°C, and the tensile strength of the resultant carbon fiber was up to 1350 MPa with a diameter around 8 µm by only heat treatment at 800°C for 5 min.

scholarly journals Effect of Heat Treatment Temperature on Martensitic Transformation and Superelasticity of the Ti49Ni51 Shape Memory Alloy

Materials ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 2539 ◽  
Author(s):  
Peiyou Li ◽  
Yongshan Wang ◽  
Fanying Meng ◽  
Le Cao ◽  
Zhirong He
Keyword(s):  
Heat Treatment ◽  
Martensitic Transformation ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Thermal Hysteresis ◽  
Treatment Temperature ◽  
Heat Treated ◽  
Different Temperatures ◽  
Tini Phase ◽  
Rapidly Solidified

The martensitic transformation and superelasticity of Ti49Ni51 shape memory alloy heat-treatment at different temperatures were investigated. The experimental results show that the microstructures of as-cast and heat-treated (723 K) Ni-rich Ti49Ni51 samples prepared by rapidly-solidified technology are composed of B2 TiNi phase, and Ti3Ni4 and Ti2Ni phases; the microstructures of heat-treated Ti49Ni51 samples at 773 and 823 K are composed of B2 TiNi phase, and of B2 TiNi and Ti2Ni phases, respectively. The martensitic transformation of as-cast Ti49Ni51 alloy is three-stage, A→R→M1 and R→M2 transformation during cooling, and two-stage, M→R→A transformation during heating. The transformations of the heat-treated Ti49Ni51 samples at 723 and 823 K are the A↔R↔M/A↔M transformation during cooling/heating, respectively. For the heat-treated alloy at 773 K, the transformations are the A→R/M→R→A during cooling/heating, respectively. For the heat-treated alloy at 773 K, only a small thermal hysteresis is suitable for sensor devices. The stable σmax values of 723 and 773 K heat-treated samples with a large Wd value exhibit high safety in application. The 773 and 823 K heat-treated samples have large stable strain–energy densities, and are a good superelastic alloy. The experimental data obtained provide a valuable reference for the industrial application of rapidly-solidified casting and heat-treated Ti49Ni51 alloy.

Solution Processed Bi-Based Sensitized Solar Cell: Effects of Post Heat Treatment

2019 ◽  
Vol 19 (6) ◽  
pp. 3505-3510 ◽  
Author(s):  
Yik Chong Chai ◽  
Hieng Kiat Jun
Keyword(s):  
Heat Treatment ◽  
Quantum Dots ◽  
Solar Cell ◽  
Heat Treatment Temperature ◽  
Sintering Temperature ◽  
Gradual Increase ◽  
Treatment Temperature ◽  
Post Heat Treatment ◽  
Dipping Process ◽  
Sensitized Solar Cells

Nanosize semiconductors have been used as active sensitizers for the application of quantum dot-sensitized solar cells (QDSSC). “Green” sensitizers are introduced as an alternative for the toxic Cd and Pb based compounds. In this work, Bi2S3 quantum dots (QDs) were fabricated and used as sensitizers in QDSSC. QDs were grown on TiO2 electrode via solution dipping process. Although the performance of “green” QDSSC is not as high as that of CdS or CdSe based QDSSCs, its performance can be enhanced with post heat treatment. The effect is dependent on the heat treatment temperature profile where gradual increase of sintering temperature is preferred. The effects of post heat treatment on Bi2S3 sensitized TiO2 electrodes are investigated and discussed.

Structural and Photoluminescent Properties of Li-Doped ZnO Film Prepared by Sol-Gel Technique

2010 ◽  
Vol 663-665 ◽  
pp. 397-400 ◽  
Author(s):  
Peng Fei Cheng ◽  
Sheng Tao Li ◽  
Han Chen Liu ◽  
Li Xun Song ◽  
Bin Gao ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Sol Gel ◽  
Treatment Temperature ◽  
Zno Films ◽  
Zno Film ◽  
Substitutional Defect ◽  
Different Temperatures ◽  
Abnormal Phenomenon ◽  
Doped Zno ◽  
Li Content

The effect of an impurity as a donor or an acceptor in ZnO film is determined by its distribution in ZnO lattice. In this paper the distribution of Li is investigated by X-ray diffraction (XRD) and photoluminescence (PL). It is found that Li-doped ZnO films own different dependence on heat treatment temperature by contrast with pure ZnO films. For Li-doped ZnO films, although the crystallinity is promoted after heat treatment at 500oC, it is impeded effectively after heat treatment at 600oC. The abnormal phenomenon implies that Li preferential inhabits at Zn-sublattice to form a substitutional defect as an acceptor unless Li content exceeds its solubility in Zn-sublattice. The change of the PL spectra of pure ZnO films after heat treatment at different temperatures reveals that the PL peak at 650nm origins from interstitial defects. Moreover, with the increase of Li content, the intensity of the peak at 650nm decreases firstly and then increases again. This interesting changing trend further reveals that superfluous Li will enter into the octahedral interspaces as donors. As a conclusion it is proposed that it is difficult to obtain high conductive p-ZnO by monodoping of Li.

Investigation on the Influence of Precipitated Phase on Corrosion Resistance of the Ni-Based Alloys

2012 ◽  
Vol 184-185 ◽  
pp. 1038-1043
Author(s):  
Xue Hui Zhao ◽  
Zhen Quan Bai ◽  
Yao Rong Feng ◽  
An Qing Fu
Keyword(s):  
Heat Treatment ◽  
Solid Solution ◽  
Corrosion Resistance ◽  
Electron Microscope ◽  
Grain Boundaries ◽  
Aging Treatment ◽  
Treatment Temperature ◽  
Different Temperatures ◽  
Metallographic Observation ◽  
Precipitated Phases

The influence of precipitated phases in Ni-based alloys during solid solution aging treatment on the performance of Ni-based alloys was investigated by means of metallographic observation, scanning electron microscope (SEM), and transmission electron microscope (TEM). The variation of microstructure and resultant phases as a result of solid solution aging treatment at different temperatures was discussed. The results show that the heat treatment temperature has significant influences on the type as well as quantity of precipitation phases. Lots of phases precipitated at grain boundaries, the distribution of precipitated phases are characterized by mesh-like structure. The corrosion tests results indicate that there is a potential difference between grains and grain boundaries due to the precipitation of chrome carbide at grain boundaries, resulting in pitting corrosion occurred preferentially at grain boundaries, consequently, the corrosion resistance of Ni-based alloys is reduced. In order to enhance the corrosion resistance of Ni-based alloys, it is expected to control the carbon content in a lower range and proper heat treatment process to avoid large amount precipitation of chrome carbide.

scholarly journals Effects of oxidation of SiC aggregates on the sintering behaviour and microstructures of SiC-CaAl12O19 composite refractories

2021 ◽  
Vol 15 (1) ◽  
pp. 11-18
Author(s):  
Yaochen Si ◽  
Miao Xia ◽  
Hongxia Li ◽  
Honggang Sun ◽  
Ang Guo ◽  
...  
Keyword(s):  
Firing Temperature ◽  
Sintering Temperature ◽  
Raw Materials ◽  
Coal Slurry ◽  
Refractory Materials ◽  
Sintering Process ◽  
Active Oxidation ◽  
Passive Oxidation ◽  
Different Temperatures ◽  
Sintering Behaviour

In order to develop chrome-free refractory materials applicable in coal slurry gasification, SiC-CaAl12O19 (SiC-CA6) composite refractories were developed and prepared by using SiC aggregates and CA6 powders as main raw materials. The sintering behaviour of the composites was investigated. After firing at different temperatures under CO atmosphere, the effects of oxidation of SiC aggregates on the sintering behaviour and microstructures of SiC-CA6 composite refractorieswere investigated. SiC-CA6 composites could not be sintered when firing temperature was lower than 1500?C. SiC had a passive oxidation and the oxidation components were able to react with CA6 to form CaAl2Si2O8. The CaAl2Si2O8 melted into liquid when sintering temperature was in the range of 1500-1600?C, which promoted the sintering process of the SiC-CA6 composites. At temperatures above 1600 ?C, an active oxidation of SiC occurred. Simultaneously, SiC could also reacted with the SiO2(s,l) to form SiO, leading to the precipitation of Al2O3 and CaO in the liquid to generate plate-like CA6. Above this temperature, the sintering of the SiC-CA6 composite refractories was affected by the growth of CA6 and oxidation of SiC. This work demonstrates that the optimal sintering temperature for the SiC-CA6 composite refractories was 1600?C.

scholarly journals Electrical Resistivity and Tensile Strength Relationship in Heat-Treated All Aluminum Alloy Wire Conductors

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5738
Author(s):  
Nidal Alshwawreh ◽  
Baider Alhamarneh ◽  
Qutaiba Altwarah ◽  
Shamel Quandour ◽  
Shadi Barghout ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Tensile Strength ◽  
Electrical Resistivity ◽  
Aluminum Alloy ◽  
Mechanical Strength ◽  
High Performance ◽  
Treatment Time ◽  
Treatment Temperature ◽  
Exponential Relationship ◽  
And Control

Thermal processing of all aluminum alloy conductors (AAAC) is an important step that is performed to enhance the electrical and mechanical properties after the drawing process. In these 6xxx alloys, mechanical strength and electrical conductivity are normally two mutually exclusive properties. With the increased demand for high performance power conductors, it is important to understand and control microstructural evolution processes (e.g., recovery and the formation of nanoscale precipitates) in these alloys for better electrical and mechanical characteristics. In this study, heat treatment was performed on as-drawn 6201 AAAC wire conductors. The variations in tensile strength and electrical resistivity were quantitatively studied as a function of both the treatment temperature and holding time. Two wire diameters commonly used in the manufacturing of medium and high voltage power cables were used: 1.7 mm and 3.5 mm. From the obtained data, significant changes in the electrical resistivity and tensile strength were observed with increasing the treatment time. For both wire diameters, it was observed that the correlation between strength and resistivity can be described by a simple exponential relationship. This link could be useful in predicting mechanical strength by monitoring electrical resistivity variations during industrial heat treatment of AAAC wire conductors.

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