scholarly journals Fabrication and Properties of Aluminum-Containing Silicon Carbide Fibres

2007 ◽  
Vol 16 (2) ◽  
pp. 096369350701600
Author(s):  
Yuxi Yu
Keyword(s):  
Tensile Strength ◽  
Young’S Modulus ◽  
Creep Resistance ◽  
Young's Modulus ◽  
Stoichiometric Composition ◽  
Strength Test ◽  
X Ray Diffraction ◽  
Element Analysis ◽  
X Ray ◽  
Tensile Strength Test

By introducing hetero-element aluminum into ceramic precursor and then sintering, polycrystalline, stoichiometric SiC fibres can be prepared. Two types of aluminum-containing SiC fibres were fabricated by the use of aluminum-containing polycarbosilane (Al-PCS). The air-cured Al-PCS fibres were pyrolyzed in inert gas up to 13 50 °C to obtain SiC(OAl) fibres, which were converted into SiC(Al) fibres by heating in argon up to 1800 °C. The properties and performances of SiC(OAl) and SiC(Al) fibres were studied by chemical element analysis, scanning electron microscopy (SEM), X-ray diffraction (XRD), tensile strength test, heat resistance and creep resistance. These results show SiC(Al) are polycrystalline SiC fibres, have a near stoichiometric composition. The tensile strength, Young's modulus and diameter of the SiC(OAl) fibres are 2.6 GPa, 210 GPa, 12 μm, respectively. The tensile strength, Young's modulus and diameter of the SiC(Al) fibres are 2.1 GPa, 405 GPa, 10 μm, respectively. The SiC(Al) fibres have higher thermal stability, and better creep resistance than the SiC(OAl), the Nicalon and the Hi-Nicalon fibres.

Mechanical properties of FeAlSi powders prepared by mechanical alloying from different initial feedstock materials

2019 ◽  
Vol 107 (2) ◽  
pp. 207 ◽  
Author(s):  
Jaroslav Čech ◽  
Petr Haušild ◽  
Miroslav Karlík ◽  
Veronika Kadlecová ◽  
Jiří Čapek ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Alloying ◽  
Young’S Modulus ◽  
Milling Time ◽  
Young's Modulus ◽  
Element Model ◽  
X Ray Diffraction ◽  
X Ray ◽  
Powder Particles ◽  
Complete Homogenization

FeAl20Si20 (wt.%) powders prepared by mechanical alloying from different initial feedstock materials (Fe, Al, Si, FeAl27) were investigated in this study. Scanning electron microscopy, X-ray diffraction and nanoindentation techniques were used to analyze microstructure, phase composition and mechanical properties (hardness and Young’s modulus). Finite element model was developed to account for the decrease in measured values of mechanical properties of powder particles with increasing penetration depth caused by surrounding soft resin used for embedding powder particles. Progressive homogenization of the powders’ microstructure and an increase of hardness and Young’s modulus with milling time were observed and the time for complete homogenization was estimated.

scholarly journals X-ray Diffraction Analysis and Williamson-Hall Method in USDM Model for Estimating More Accurate Values of Stress-Strain of Unit Cell and Super Cells (2 × 2 × 2) of Hydroxyapatite, Confirmed by Ultrasonic Pulse-Echo Test

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2949
Author(s):  
Marzieh Rabiei ◽  
Arvydas Palevicius ◽  
Amir Dashti ◽  
Sohrab Nasiri ◽  
Ahmad Monshi ◽  
...  
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
Ultrasonic Pulse ◽  
High Accuracy ◽  
Unit Cell ◽  
Deformation Model ◽  
X Ray Diffraction ◽  
Uniform Deformation ◽  
X Ray ◽  
Pulse Echo

Taking into account X-ray diffraction, one of the well-known methods for calculating the stress-strain of crystals is Williamson-Hall (W–H). The W-H method has three models, namely (1) Uniform deformation model (UDM); (2) Uniform stress deformation model (USDM); and (3) Uniform deformation energy density model (UDEDM). The USDM and UDEDM models are directly related to the modulus of elasticity (E). Young’s modulus is a key parameter in engineering design and materials development. Young’s modulus is considered in USDM and UDEDM models, but in all previous studies, researchers used the average values of Young’s modulus or they calculated Young’s modulus only for a sharp peak of an XRD pattern or they extracted Young’s modulus from the literature. Therefore, these values are not representative of all peaks derived from X-ray diffraction; as a result, these values are not estimated with high accuracy. Nevertheless, in the current study, the W-H method is used considering the all diffracted planes of the unit cell and super cells (2 × 2 × 2) of Hydroxyapatite (HA), and a new method with the high accuracy of the W-H method in the USDM model is presented to calculate stress (σ) and strain (ε). The accounting for the planar density of atoms is the novelty of this work. Furthermore, the ultrasonic pulse-echo test is performed for the validation of the novelty assumptions.

Elastic Properties and Structural Evolution of AgNi Superlattices

1991 ◽  
Vol 229 ◽  
Author(s):  
B. Rodmacq ◽  
V. Pelosin ◽  
J. Hillairet
Keyword(s):  
Young’S Modulus ◽  
Elastic Properties ◽  
Young's Modulus ◽  
Functional Dependence ◽  
Structural Evolution ◽  
X Ray Diffraction ◽  
X Ray ◽  
Tension Tests ◽  
Prepared State ◽  
Dimensional Variation

AbstractSilver-nickel multilayers were prepared by sputtering at 100 K. X-ray diffraction, electrical resistivity and dimensional variation measurements were performed to structurally characterize these stratified materials, both in the as-prepared state and during the course of annealing cycles. Clearly, polycrystalline superlattices with marked (111) texture perpendicular to the strata are formed. We studied the elastic properties of these superlattices by performing uniaxial tension tests. No deviation from linear elasticity was observed, whatever the period. Young's modulus was found to be 130±15 GPa for all the periods studied. Thus no significant functional dependence of Young's modulus on the stacking periodicity exists in the AgNi superlattice, in the range of periods explored, 2.6 to 18 nm.

Electrospun Gelatin/Hydroxyapatite Nanocomposite Scaffolds for Bone Tissue Engineering

2008 ◽  
Vol 1094 ◽  
Author(s):  
Shane Catledge ◽  
Parul Tyagi ◽  
Mark Koopman ◽  
Andrei Stanishevsky ◽  
Yogesh K. Vohra
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
Fibrous Composite ◽  
X Ray Diffraction ◽  
Composite Scaffolds ◽  
X Ray ◽  
Structure And Morphology ◽  
Electrospun Gelatin ◽  
Nanocomposite Scaffolds ◽  
Nanoscale Level

AbstractElectrospun composite scaffolds were prepared by mixing gelatin with nanoparticles of hydroxyapatite (nanoHA) in 2,2,2-trifluoroethanol (TFE) solution. The fibrous composite scaffolds with nanoHA content from 0 to 40 wt% were compared in terms of structure and morphology via x-ray diffraction (XRD) and scanning electron microscopy (SEM). Results show that dispersion of nanoHA in the scaffolds is uniform for 0%, 10%, 20%, and 30% nanoHA content, but significant nanoHA agglomeration can be observed for scaffolds with 40% nanoHA. In order to study the effect of nanoHA content on mechanical properties at the nanoscale level, the fibrous scaffolds were pressed into dense pellets and tested by nanoindentation to determine Young's modulus. Young's modulus was found to increase linearly with nanoHA content, reaching unexpectedly high values of 10.2 ± 0.8 GPa. Results are compared with other polymer/HA composites including those made with polycaprolactone or collagen.

NANOMECHANICAL BEHAVIOR OF HUMAN MOLARS SOAKED IN SLIGHT ACID SOLUTIONS

2009 ◽  
Vol 23 (26) ◽  
pp. 3115-3124
Author(s):  
TE-HUA FANG ◽  
WIN-JIN CHANG ◽  
SHAO-HUI KANG ◽  
CHIA-CHUN CHU
Keyword(s):  
Electron Microscope ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Hexagonal Phase ◽  
Chemical Properties ◽  
Acid Solutions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hydroxyl Apatite ◽  
And Chemical Properties

This paper studied the mechanical and chemical properties of hydroxyl apatite (HA) crystal structure in the teeth when human molars were soaked in slight acid solution. First, we soaked the ground and polished molars respectively in the liquor of 30 wt.% H 2 CO 3 and the liquor of 30 wt.% H 2 O 2 for 10, 20, or 60 minutes. Next, we used a nanoindenter to measure the hardness and Young's modulus. Finally, we used a scanning electron microscope (SEM) coupled with energy dispersive spectroscopy (EDS) to analyze the variation of Ca , P and Na in teeth, a high resolution transmitting electron microscope (HRTEM) to observe the arrangement of crystallization phase of HA, and X-ray diffraction (XRD) to analyze the crystallinity of the hexagonal phase of HA. The results showed that the demineralization phenomenon of the calcium–phosphorous compound in teeth made the teeth reduce sharply in hardness and Young's modulus after they were soaked in the two slight acid solutions for 10 minutes, but the re-mineralization phenomenon made the hardness and Young's modulus ascend gradually when the time lasted longer. With the same period of time, the teeth soaked in H 2 CO 3 were lower in the hardness and Young's modulus than that in H 2 O 2.

Obtaining and Characterizing Nylon 6.12-Pseudoboehmite Nanocomposites - Mechanic Tests

2016 ◽  
Vol 97 ◽  
pp. 3-10
Author(s):  
Antônio Hortêncio Munhoz Jr. ◽  
Alber Luiz do Nascimento ◽  
Cesar Denuzzo ◽  
Gabriel Cavalcante Gomes ◽  
Leila Figueiredo de Miranda ◽  
...  
Keyword(s):  
Inorganic Material ◽  
Elasticity Modulus ◽  
Mechanical Test ◽  
High Specific Surface Area ◽  
Strength Test ◽  
Polymeric Matrix ◽  
Bending Test ◽  
X Ray Diffraction ◽  
X Ray ◽  
Tensile Strength Test

Polymer nanocomposites are formed by nanometrical particles embedded in a matrix. Additions of small amounts of nanoparticles of inorganic material in polymer matrixes can greatly improve mechanical properties when compared with the pure polymer. The high specific surface area of the inorganic nanoparticle materials promotes its dispersion in the polymeric matrix and the resulting properties are strongly related to the homogeneity of the dispersion. In the present work, nylon 6.12 nanocomposites with aged pseudoboehmite were obtained using octadecylamine to improve the union between the polymer and the pseudoboehmite. The nanocomposites were characterized by thermal and mechanical test. The pseudoboehmite was characterized by scanning electron microscopy and x-ray diffraction. The nanocomposite was characterized by tensile strength test, 3 points bending test and impact Izod resistance test. The addition of pseudoboehmite promote the increase of the elasticity modulus evidencing the interaction of the pseudoboehmite with the polymeric matrix, probably modifying its crystalline structure. The addition of pseudoboehmite promoted an increase in the HDT an Vicat temperatures of the nanocomposite.

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