The impact of heat-treatment protocol on the grain size and ionic conductivity of NASICON glass-ceramics

2020 ◽  
Vol 40 (15) ◽  
pp. 5634-5645 ◽  
Author(s):  
Adriana M. Nieto-Muñoz ◽  
Jairo F. Ortiz-Mosquera ◽  
Ana C.M. Rodrigues
Keyword(s):  
Heat Treatment ◽  
Grain Size ◽  
Ionic Conductivity ◽  
Treatment Protocol ◽  
Glass Ceramics ◽  
The Impact

Ionic conductivity in nanocrystalline Gd doped ceria

2008 ◽  
Vol 1122 ◽  
Author(s):  
Gianguido Baldinozzi ◽  
David Simeone ◽  
Dominique Gosset ◽  
Mickael Dollé ◽  
Georgette Petot-Ervas
Keyword(s):  
Grain Size ◽  
Ionic Conductivity ◽  
Sol Gel ◽  
Doped Ceria ◽  
Narrow Size Distribution ◽  
Conductivity Measurements ◽  
X Ray Diffraction ◽  
X Ray ◽  
Grain Sizes ◽  
The Impact

AbstractWe have synthesized Gd-doped ceria polycrystalline samples (5, 10, 15 %mol), having relative densities exceeding 95% and grain sizes between 30 and 160 nm after axial hot pressing (750 °C, 250 MPa). The samples were prepared by sintering nanopowders obtained by sol-gel chemistry methods having a very narrow size distribution centered at about 16 nm. SEM and X-ray diffraction were performed to characterize the sample microstructures and to assess their structures. We report ionic conductivity measurements using impedance spectroscopy. It is important to investigate the properties of these systems with sub-micrometric grains and as a function of their composition. Therefore, samples having micrometric and nanometric grain sizes (and different Gd content) were studied. Evidence of Gd segregation near the grain boundaries is given and the impact on the ionic conductivity, as a function of the grain size and Gd composition, is discussed and compared to microcrystalline samples.

scholarly journals Strength Behaviour of Hot Die Steel with Respect to its Heat Treatment

2020 ◽  
Vol 9 (1) ◽  
pp. 2100-2102
Keyword(s):  
Heat Treatment ◽  
Grain Size ◽  
Tensile Strength ◽  
Tensile Test ◽  
Uniaxial Tensile ◽  
Uniaxial Tensile Test ◽  
Austenitizing Temperature ◽  
Tempering Temperature ◽  
Die Steel ◽  
The Impact

The surface temperature of hot die steel reaches typically up to 550ºC or above during processes like hot extrusion and casting non-ferrous material. The present paper explores the impact of austenitizing temperature as well as tempering temperature on the tensile strength of hot die steel. Heat treatment is done at three different austenitizing temperatures of 1010ºC, 1030ºC, and 1050ºC, followed by tempering done at two different temperatures of 540ºC and 580°C. Tempering is done twice for two hours. Metallographic grinding, polishing, and then etching using 2% Nital is done to investigate the microstructure of hot die steel with respect to its heat treatment. It is found that the grain size of hot die steel increases with an increase in austenitizing temperature. The impact on tensile strength of hot die steel for its heat treatment is examined by conducting the uniaxial tensile test to fracture. And investigation of the morphology of the fracture surface produced after the tensile test is done. It was found that hot die steel with large grain size exhibits lesser tensile strength. Whereas, the one having smaller grain has higher tensile strength that is found to be in accordance with the Hall-Patch equation

Preparation and Characterization of Na2O-Y2O3-P2O5-SiO2 Transparent Glass Ceramics

2018 ◽  
Vol 281 ◽  
pp. 692-698 ◽  
Author(s):  
Meng Jie Zhao ◽  
Xiang Yu Zou ◽  
Qin Lei Wei ◽  
Shuo Meng ◽  
Hong Bo Zhang ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Refractive Index ◽  
Glass Ceramic ◽  
Visible Region ◽  
Glass Ceramics ◽  
Scanning Calorimetry ◽  
Transparent Glass ◽  
Diffraction Patterns ◽  
The Impact ◽  
Precursor Glass

Transparent glass ceramics containing Na3.6Y1.8(PO4)3 crystals were successfully synthesized using high temperature melting quenching and subsequent heat treatment of the precursor glass with a composition 15Na2CO3-3Y2O3-45SiO2-31H3BO3- 5.4P2O5-0.6Sb2O3 (mol%). The impact of heat treatment is investigated in detail. The glass sample was tested by differential scanning calorimetry analysis to determine the heat treatment system. The ideal heat-treated condition is at 650°C for 2 h. The structure and morphology properties were systematically analyzed by recording X-ray diffraction patterns and scanning electron microscopy images, which indicate that Na3.6Y1.8(PO4)3 crystal were precipitated homogeneously among the glass matrix. The microstructural of precursor glass and glass ceramic were compared by analyzing FTIR spectra, indicating the formation of phosphate groups in glass ceramic. The refractive index of glass ceramics samples were measured. In the visible region, the transmittance of glass ceramics is up to 85%. Moreover, the relationship between the refractive index of the sample and the transmittance is discussed.

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.

scholarly journals B2O3-Doped LATP Glass-Ceramics Studied by X-ray Diffractometry and MAS NMR Spectroscopy Methods

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 390
Author(s):  
Wioleta Ślubowska ◽  
Lionel Montagne ◽  
Olivier Lafon ◽  
François Méar ◽  
Konrad Kwatek
Keyword(s):  
Heat Treatment ◽  
Glass Ceramics ◽  
Lithium Ion ◽  
Magic Angle Spinning ◽  
Mas Nmr ◽  
Magic Angle ◽  
Nmr Studies ◽  
X Ray ◽  
Glass Forming ◽  
The Impact

Two families of glasses in the Li2O-Al2O3-B2O3-TiO2-P2O5 system were prepared via two different synthesis routes: melt-quenching and ball-milling. Subsequently, they were submitted to crystallization and yielded the Li1.3Al0.3Ti1.7(PO4)3 (LATP)-based glass-ceramics. Glasses and corresponding glass-ceramics were studied by complementary X-ray diffraction (XRD) and 27Al, 31P, 7Li, 11B magic-angle spinning nuclear magnetic resonance (MAS NMR) methods in order to compare their structure and phase composition and elucidate the impact of boron additive on their glass-forming properties and crystallization process. XRD studies show that the addition of B2O3 improves the glass-forming properties of glasses prepared by either method and inhibits the precipitation of unwanted phases during heat treatment. MAS NMR studies allowed us to distinguish two LATP phases of slightly different chemical composition suggesting that LATP grains might not be homogeneous. In conclusion, the crystallization of boron-incorporated LATP glasses can is an effective way of obtaining LATP-based solid state electrolytes for the next generation of lithium-ion batteries provided the proper heat-treatment conditions are chosen.

Microstructural and Mechanical Behaviour Evaluation of Mg-Al-Zn Alloy Friction Stir Welded Joint

2020 ◽  
Vol 17 (3) ◽  
pp. 8150-8159
Author(s):  
Kulwant Singh ◽  
Gurbhinder Singh ◽  
Harmeet Singh
Keyword(s):  
Heat Treatment ◽  
Friction Stir Welding ◽  
Magnesium Alloys ◽  
Mechanical Performance ◽  
Fuel Efficiency ◽  
Research Work ◽  
Grain Structure ◽  
Tensile Fracture ◽  
Friction Stir ◽  
The Impact

The weight reduction concept is most effective to reduce the emissions of greenhouse gases from vehicles, which also improves fuel efficiency. Amongst lightweight materials, magnesium alloys are attractive to the automotive sector as a structural material. Welding feasibility of magnesium alloys acts as an influential role in its usage for lightweight prospects. Friction stir welding (FSW) is an appropriate technique as compared to other welding techniques to join magnesium alloys. Field of friction stir welding is emerging in the current scenario. The friction stir welding technique has been selected to weld AZ91 magnesium alloys in the current research work. The microstructure and mechanical characteristics of the produced FSW butt joints have been investigated. Further, the influence of post welding heat treatment (at 260 °C for 1 h) on these properties has also been examined. Post welding heat treatment (PWHT) resulted in the improvement of the grain structure of weld zones which affected the mechanical performance of the joints. After heat treatment, the tensile strength and elongation of the joint increased by 12.6 % and 31.9 % respectively. It is proven that after PWHT, the microhardness of the stir zone reduced and a comparatively smoothened microhardness profile of the FSW joint obtained. No considerable variation in the location of the tensile fracture was witnessed after PWHT. The results show that the impact toughness of the weld joints further decreases after post welding heat treatment.

scholarly journals Lightweight Cement Conglomerates Based on End-of-Life Tire Rubber: Effect of the Grain Size, Dosage and Addition of Perlite on the Physical and Mechanical Properties

Materials ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 225
Author(s):  
Andrea Petrella ◽  
Michele Notarnicola
Keyword(s):  
Grain Size ◽  
End Of Life ◽  
Compression Tests ◽  
Tire Rubber ◽  
Impact Compression ◽  
Weight Percentage ◽  
Deep Groove ◽  
Mechanical Strengths ◽  
The Impact ◽  
Thermal Conductivities

Lightweight cement mortars containing end-of-life tire rubber (TR) as aggregate were prepared and characterized by rheological, thermal, mechanical, microstructural, and wetting tests. The mixtures were obtained after total replacement of the conventional sand aggregate with untreated TR with different grain sizes (0–2 mm and 2–4 mm) and distributions (25%, 32%, and 40% by weight). The mortars showed lower thermal conductivities (≈90%) with respect to the sand reference due to the differences in the conductivities of the two phases associated with the low density of the aggregates and, to a minor extent, to the lack of adhesion of tire to the cement paste (evidenced by microstructural detection). In this respect, a decrease of the thermal conductivities was observed with the increase of the TR weight percentage together with a decrease of fluidity of the fresh mixture and a decrease of the mechanical strengths. The addition of expanded perlite (P, 0–1 mm grain size) to the mixture allowed us to obtain mortars with an improvement of the mechanical strengths and negligible modification of the thermal properties. Moreover, in this case, a decrease of the thermal conductivities was observed with the increase of the P/TR dosage together with a decrease of fluidity and of the mechanical strengths. TR mortars showed discrete cracks after failure without separation of the two parts of the specimens, and similar results were observed in the case of the perlite/TR samples thanks to the rubber particles bridging the crack faces. The super-elastic properties of the specimens were also observed in the impact compression tests in which the best performances of the tire and P/TR composites were evidenced by a deep groove before complete failure. Moreover, these mortars showed very low water penetration through the surface and also through the bulk of the samples thanks to the hydrophobic nature of the end-of-life aggregate, which makes these environmentally sustainable materials suitable for indoor and outdoor elements.

scholarly journals Grain Size Evolution and Mechanical Properties of Nb, V–Nb, and Ti–Nb Boron Type S1100QL Steels

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 492
Author(s):  
Jan Foder ◽  
Jaka Burja ◽  
Grega Klančnik
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Grain Size ◽  
Hot Forging ◽  
Size Control ◽  
High Strength ◽  
Fatigue Properties ◽  
Titanium Addition ◽  
Austenite Grain Size ◽  
Size Evolution

Titanium additions are often used for boron factor and primary austenite grain size control in boron high- and ultra-high-strength alloys. Due to the risk of formation of coarse TiN during solidification the addition of titanium is limited in respect to nitrogen. The risk of coarse nitrides working as non-metallic inclusions formed in the last solidification front can degrade fatigue properties and weldability of the final product. In the presented study three microalloying systems with minor additions were tested, two without any titanium addition, to evaluate grain size evolution and mechanical properties with pre-defined as-cast, hot forging, hot rolling, and off-line heat-treatment strategy to meet demands for S1100QL steel. Microstructure evolution from hot-forged to final martensitic microstructure was observed, continuous cooling transformation diagrams of non-deformed austenite were constructed for off-line heat treatment, and the mechanical properties of Nb and V–Nb were compared to Ti–Nb microalloying system with a limited titanium addition. Using the parameters in the laboratory environment all three micro-alloying systems can provide needed mechanical properties, especially the Ti–Nb system can be successfully replaced with V–Nb having the highest response in tensile properties and still obtaining satisfying toughness of 27 J at –40 °C using Charpy V-notch samples.

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