scholarly journals INVESTIGATION OF PRESSING DIAGRAMS DURING MOLDING A MIXTURE OF COPPER POWDERS AND SILICON CARBIDE

2020 ◽  
pp. 672-680
Author(s):  
Николай Александрович Панькин ◽  
Александр Федорович Сигачев ◽  
Владимир Петрович Мишкин
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Silicon Carbide ◽  
Inelastic Deformation ◽  
Structural Elements ◽  
Cold Forming ◽  
Copper Powders ◽  
Hydrostatic Weighing ◽  
Closed Mold ◽  
Scanning Electron

Проведено исследование смеси порошков меди и карбида кремния после одностороннего холодного формования в закрытой пресс-форме методами: растровой электронной микроскопии, гидростатического взвешивания и анализа диаграмм прессования. Выявлены основные этапы формования, их границы и характерные процессы, происходящие на каждом из них. Установлено, что на диаграмме формования можно выделить не менее трёх областей. Показано, что их границы (по давлению) определяются механическими свойствами материалов используемых порошков и процессами перераспределения / укладки структурных элементов и их упругой/неупругой деформации. A study of a mixture of copper and silicon carbide powders after one-sided cold forming in a closed mold was carried out by methods: scanning electron microscopy, hydrostatic weighing and analysis of pressing diagrams. The main stages of molding, their boundaries and characteristic processes occurring at each of them are identified. It was found that at least three areas can be distinguished on the molding diagram. It is shown that their boundaries (in terms of pressure) are determined by the mechanical properties of the materials of the powders used and the processes of redistribution / packing of structural elements and their elastic / inelastic deformation.

STUDY OF MECHANICAL PROPERTIES AND FRACTURE MODE OF ALUMINA-SILICON CARBIDE NANOCOMPOSITES

2012 ◽  
Vol 05 ◽  
pp. 551-558 ◽  
Author(s):  
A. RAHIMNEZHAD YAZDI ◽  
H.R. BAHARVANDI ◽  
H. ABDIZADEH ◽  
N. EHSANI
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Silicon Carbide ◽  
Flexural Strength ◽  
Fracture Mode ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sic Particles ◽  
Scanning Electron

In this study Al 2 O 3- SiC nanocomposites have been fabricated by mixing of alumina and silicon carbide nano powders, followed by hot pressing at 1700°C. The mechanical properties and fracture mode of Al 2 O 3- SiC nanocomposites containing different volume fractions (5, 10 and 15%) of nano scale SiC particles were investigated and compared with those of alumina. Al 2 O 3- SiC powders were prepared by planetary milling in isopropanol. Fracture mode of specimens was investigated by means of scanning electron microscopy. Nanocomposites were tougher than alumina when they were hot pressed at the same temperature, and the values of nanocomposite's flexural strength and hardness were higher than those of alumina. Flexural strength, hardness and fracture toughness of the nanocomposites increase by increasing the volume percent of SiC up to 10% and then decrease slightly. The Scanning electron microscopy observations showed that fracture mode changes from intergranular for alumina to transgranular for nanocomposites. Finally X-ray diffraction analysis couldn't detect any chemical reactions between Al 2 O 3 and SiC particles.

scholarly journals Механические свойства композитного покрытия SiC на графите, полученного методом замещения атомов

2021 ◽  
Vol 47 (20) ◽  
pp. 7
Author(s):  
А.С. Гращенко ◽  
С.А. Кукушкин ◽  
А.В. Осипов ◽  
А.В. Редьков
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Silicon Carbide ◽  
Mechanical Characteristics ◽  
Composite Coatings ◽  
Continuous Film ◽  
Silicon Melt ◽  
First Time ◽  
Initial Graphite ◽  
Scanning Electron

The mechanical properties of composite coatings made of silicon carbide on graphite are studied for the first time. For the deposition of coatings, a new method of annealing the initial graphite was used, which was in contact with a silicon melt in an atmosphere of carbon monoxide.The samples were studied by nanoindentation and scanning electron microscopy. It is shown that the formed coating consists of a continuous film of monocrystalline silicon carbide lying on the surface, dendrites and crystalline druses, with roots going deep into the sample through a system of pores. It is shown that the coating significantly increases the mechanical characteristics of the graphite surface, including the microhardness.

Failure Analysis of Corrugated Hoses

2017 ◽  
Vol 270 ◽  
pp. 68-73
Author(s):  
Lenka Klakurková ◽  
Miroslava Horynová ◽  
Martin Juliš ◽  
Pavel Gejdoš ◽  
Lucie Páleníková ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Stainless Steel ◽  
Service Life ◽  
Aisi 316L ◽  
Cooling Systems ◽  
Cold Forming ◽  
Water Gas ◽  
Scanning Electron

Stainless steel corrugated hoses are widely used in many areas of industry. They are used in application such as distribution of drinking and supply water, gas and also various working fluids, for example in cooling systems. During the assembly of AISI 316L corrugated hoses for cooling systems defects form due to deformation of the hoses during assembly. The absolute tightness of such systems is required and any defects of the hoses are therefore undesirable. This study deals with evaluation of most common defects of corrugated hoses via light and scanning electron microscopy and proposes measures to minimize such defects. It was revealed, that defects form due to deformation of the hoses during assembly or, in case of unfavorable microstructure, during the service life. In later case, failure of the hose was caused by higher content of deformation-induced martensite in microstructure as a result of intense cold forming. Component with such microstructure exhibited less favorable mechanical properties and hoses were more prone to the failure.

scholarly journals Morphology and Characterisation of Novolac–LDPE-Based Mixtures as Matrix for Injection Moulded Green Bodies for Bio-Based SiC Ceramics

Ceramics ◽  
2019 ◽  
Vol 2 (3) ◽  
pp. 536-550
Author(s):  
Mihalic ◽  
Soares de Sousa ◽  
Burzic ◽  
Hinterreiter ◽  
Stifter ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Silicon Carbide ◽  
Mechanical Testing ◽  
Strong Influence ◽  
Phase Distribution ◽  
Process Chain ◽  
Sic Ceramics ◽  
Scanning Electron

This work focuses on the influence of the composition of novolac–LDPE-based mixtures, which serve as a matrix for the green bodies for bio-based silicon carbide (C/Si/SiC) ceramics, on the morphology and the mechanical properties of the green bodies and the ceramics produced thereof. The green bodies were obtained through compounding and injection moulding, and were characterised by scanning electron microscopy (SEM) and mechanical testing. Selected formulations were reinforced with natural fibres, pyrolysed to yield porous carbon templates, and converted into C/Si/SiC ceramics via liquid silicon infiltration. The carbon and ceramic specimens were characterised by light optical microscopy (LOM) and mechanical testing. Without further additives, very coarse morphologies of the novolac–LDPE-based mixtures were obtained, but the miscibility could be improved by the addition of a coupling agent and a lubricant. The pore structure of the carbon specimens was dependent on the phase distribution in the green bodies, and in turn determined the morphology of the C/Si/SiC ceramics. In all steps of the process chain, the morphology had a very strong influence on the mechanical properties. From green bodies with a homogeneous phase distribution, ceramic specimens with a SiC content of up to 75 vol% could be obtained.

Structure and Properties Study of Porous Silicon Carbide Composite Based on SLA

2011 ◽  
Vol 194-196 ◽  
pp. 1590-1593
Author(s):  
Jie Jin ◽  
Maolin Ni ◽  
Shen Hao Wang
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Silicon Carbide ◽  
Corrosion Resistance ◽  
Porous Silicon ◽  
Structure And Properties ◽  
Porous Silicon Carbide ◽  
Carbide Composite ◽  
Scanning Electron

In the article, porous silicon carbide composite is prepared based on stereo lithography apparatus (SLA). The microstructure of porous silicon carbide composite is characterized by mean of scanning electron microscopy (SEM). The properties of porous silicon carbide composite are studied, such as surface HV and corrosion resistance, and the influence of the pore agent content to mechanical properties.

Electron Microscopic Observation of the Longitudinal Organization of Poly (p-Phenylene Terephthalamide) Fibers

1982 ◽  
Vol 40 ◽  
pp. 680-681
Author(s):  
Li Li-Sheng ◽  
L.F. Allard ◽  
W.C. Bigelow
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Microscopic Observation ◽  
Electron Microscopic Observation ◽  
Electron Microscopic ◽  
Aromatic Polyamides ◽  
Radial Arrangement ◽  
Scanning Electron ◽  
Better Than

The aromatic polyamides form a class of fibers having mechanical properties which are much better than those of aliphatic polyamides. Currently, the accepted morphology of these fibers as proposed by M.G. Dobb, et al. is a radial arrangement of pleated sheets, with the plane of the pleats parallel to the axis of the fiber. We have recently obtained evidence which supports a different morphology of this type of fiber, using ultramicrotomy and ion-thinning techniques to prepare specimens for transmission and scanning electron microscopy.

scholarly journals Analysis of PLA Composite Filaments Reinforced with Lignin and Polymerised-Lignin-Treated NFC

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2174
Author(s):  
Diana Gregor-Svetec ◽  
Mirjam Leskovšek ◽  
Blaž Leskovar ◽  
Urška Stanković Elesini ◽  
Urška Vrabič-Brodnjak
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Tensile Strength ◽  
Glassy State ◽  
Nanofibrillated Cellulose ◽  
Dynamic Mechanical Properties ◽  
Initial Modulus ◽  
Surface Modified ◽  
Scanning Electron

Polylactic acid (PLA) is one of the most suitable materials for 3D printing. Blending with nanoparticles improves some of its properties, broadening its application possibilities. The article presents a study of composite PLA matrix filaments with added unmodified and lignin/polymerised lignin surface-modified nanofibrillated cellulose (NFC). The influence of untreated and surface-modified NFC on morphological, mechanical, technological, infrared spectroscopic, and dynamic mechanical properties was evaluated for different groups of samples. As determined by the stereo and scanning electron microscopy, the unmodified and surface-modified NFCs with lignin and polymerised lignin were present in the form of plate-shaped agglomerates. The addition of NFC slightly reduced the filaments’ tensile strength, stretchability, and ability to absorb energy, while in contrast, the initial modulus slightly improved. By adding NFC to the PLA matrix, the bending storage modulus (E’) decreased slightly at lower temperatures, especially in the PLA samples with 3 wt% and 5 wt% NFC. When NFC was modified with lignin and polymerised lignin, an increase in E’ was noticed, especially in the glassy state.

scholarly journals Corrosion Behavior and Mechanical Properties of a Nanocomposite Superhydrophobic Coating

Coatings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 652
Author(s):  
Divine Sebastian ◽  
Chun-Wei Yao ◽  
Lutfun Nipa ◽  
Ian Lian ◽  
Gary Twu
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Atomic Force Microscopy ◽  
Nanocomposite Coating ◽  
Superhydrophobic Coating ◽  
Force Microscopy ◽  
Atomic Force ◽  
Microscopy Images ◽  
Scanning Electron

In this work, a mechanically durable anticorrosion superhydrophobic coating is developed using a nanocomposite coating solution composed of silica nanoparticles and epoxy resin. The nanocomposite coating developed was tested for its superhydrophobic behavior using goniometry; surface morphology using scanning electron microscopy and atomic force microscopy; elemental composition using energy dispersive X-ray spectroscopy; corrosion resistance using atomic force microscopy; and potentiodynamic polarization measurements. The nanocomposite coating possesses hierarchical micro/nanostructures, according to the scanning electron microscopy images, and the presence of such structures was further confirmed by the atomic force microscopy images. The developed nanocomposite coating was found to be highly superhydrophobic as well as corrosion resistant, according to the results from static contact angle measurement and potentiodynamic polarization measurement, respectively. The abrasion resistance and mechanical durability of the nanocomposite coating were studied by abrasion tests, and the mechanical properties such as reduced modulus and Berkovich hardness were evaluated with the aid of nanoindentation tests.

Effect of Sintering Temperature on Microstructure and Mechanical Properties of Al2O3-TiC-ZrO2 Ceramic Composites

2012 ◽  
Vol 476-478 ◽  
pp. 1031-1035
Author(s):  
Wei Min Liu ◽  
Xing Ai ◽  
Jun Zhao ◽  
Yong Hui Zhou
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Fracture Toughness ◽  
Flexural Strength ◽  
Relative Density ◽  
Sintering Temperature ◽  
Ceramic Composites ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

Al2O3-TiC-ZrO2ceramic composites (ATZ) were fabricated by hot-pressed sintering. The phases and microstructure of the composites were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The relative density and mechanical properties (flexural strength, fracture toughness and Vicker’s hardness) of the composites were tested. The results show that the microstructure of the composites was the gray core-white rim. With the increase of sintering temperature, the relative density and mechanical properties of the composites increased first and then decreased. The composite sintered at 1705°C has the highest synthetical properties, and its relative density, flexural strength, fracture toughness and Vickers hardness are 98.3%,970MPa,6.0 MPa•m1/2and 20.5GPa, respectively.

Research on compatibility and surface of high impact bio-based polyamide

2021 ◽  
pp. 095400832110055
Author(s):  
Yang Wang ◽  
Yuhui Zhang ◽  
Yuhan Xu ◽  
Xiucai Liu ◽  
Weihong Guo
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Differential Scanning Calorimetry ◽  
Crystallization Behavior ◽  
High Impact ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Scanning Electron

The super-tough bio-based nylon was prepared by melt extrusion. In order to improve the compatibility between bio-based nylon and elastomer, the elastomer POE was grafted with maleic anhydride. Scanning Electron Microscopy (SEM) and Thermogravimetric Analysis (TGA) were used to study the compatibility and micro-distribution between super-tough bio-based nylon and toughened elastomers. The results of mechanical strength experiments show that the 20% content of POE-g-MAH has the best toughening effect. After toughening, the toughness of the super-tough nylon was significantly improved. The notched impact strength was 88 kJ/m2 increasing by 1700%, which was in line with the industrial super-tough nylon. X-ray Diffraction (XRD) and Differential Scanning Calorimetry (DSC) were used to study the crystallization behavior of bio-based PA56, and the effect of bio-based PA56 with high crystallinity on mechanical properties was analyzed from the microstructure.

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