scholarly journals EFFECT OF THE MICROWAVE ELECTROMAGNETIC FIELD ON DEFECT FORMATION UNDER THE INFLUENCE OF ENVIRONMENTAL FACTORS IN CURED CARBON FIBER

2021 ◽  
pp. 34-36
Author(s):  
I. V. Zlobina
Keyword(s):  
Electromagnetic Field ◽  
Carbon Fiber ◽  
Environmental Factors ◽  
Defect Formation ◽  
Strength Characteristics ◽  
Interlaminar Shear ◽  
Kinetics Of ◽  
Maximum Stresses

The article presents the results of researches of influence of modification of the cured CFRP in a microwave electromagnetic field to change the kinetics of defect formation and strength characteristics under the influence of environmental factors, showed the increase of the maximum stresses interlaminar shear specimens after exposure in situ by 16,5% compared with the control.

scholarly journals REDUCING THE INFLUENCE OF ENVIRONMENTAL FACTORS ON THE BENDING DEFORMATION OF CURED CARBON FIBER BY MICROWAVE PROCESSING

2021 ◽  
pp. 56-58
Author(s):  
I. V. Zlobina
Keyword(s):  
Electromagnetic Field ◽  
Composite Materials ◽  
Carbon Fiber ◽  
Environmental Factors ◽  
Flux Density ◽  
Environmental Conditions ◽  
Climatic Factors ◽  
Transverse Load ◽  
Bending Deformation ◽  
Energy Flux Density

The article discusses the results of a study of bending deformation and creep under transverse load of cured polymer composite materials (PCM), which were located for 8 months in full-scale environmental conditions in Saratov. It was found that being under the influence of natural climatic factors for the specified time leads to an increase in the bending deformation of samples from 13,5 to 25,4%, depending on the load. Processing in a microwave electromagnetic field with a frequency of 2450 MHz with an energy flux density of (17-18) x10 mW / cm for 2 minutes reduces bending deformation by (9-18)%, and creep - up to 4 times.

ASSESSMENT OF THE STABILITY OF CARBON FIBER TO THE ACTION OF TRANSVERSE LOADS TAKING INTO ACCOUNT TIME AND CLIMATE FACTORS

2021 ◽  
pp. 3-11
Author(s):  
I. V. Zlobina
Keyword(s):  
Electromagnetic Field ◽  
Carbon Fiber ◽  
Environmental Factors ◽  
Bending Strength ◽  
Negative Influence ◽  
Strengthening Effect ◽  
Functional Dependencies ◽  
Experimental Conditions ◽  
Term Operation ◽  
The Stability

The relevance of research in the development of physical methods for increasing the stability of products made of polymer composite materials (PCM) to the influence of environmental factors, taking into account its duration, is shown. The influence of exposure of carbon fiber samples on an epoxy matrix in the natural conditions of the climate zone of Saratov on the change in the limit stresses of three-point bending was studied. Comparative tests of samples premodified in a microwave electromagnetic field with a frequency of 2.45 GHz with an energy flux density (17…18)×104 µw/cm2 were performed. It is shown that the influence of environmental factors leads to a decrease in the limit stresses by (3,7…10,4) % depending on the exposure. Modification of carbon fiber in the cured state in the microwave electromagnetic field reduces the negative influence of the external environment by reducing the strength by (44.3…73) %. It was found that the strengthening effect of microwave modification increases with increasing exposure from 6 % to 11.5 % under the accepted experimental conditions, while the uniformity of the bending strength values in the batch increases significantly, which is manifested in a decrease in the coefficient of variation of limit stresses by (70.2…77.8) %. Functional dependencies in the form of 2nd-order polynomials are obtained, allowing with confidence (98…99) % predict the stability of products made of modified carbon fiber during long-term operation under the influence of environmental factors.

scholarly journals In Situ Study on Fracture Behavior of Z-Pinned Carbon Fiber-Reinforced Aluminum Matrix Composite via Scanning Electron Microscope (SEM)

Materials ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 1941
Author(s):  
Yunhe Zhang ◽  
Sian Wang ◽  
Xiwang Zhao ◽  
Fanming Wang ◽  
Gaohui Wu
Keyword(s):  
Stainless Steel ◽  
Shear Strength ◽  
Electron Microscope ◽  
Carbon Fiber ◽  
Aluminum Matrix ◽  
Aluminum Matrix Composite ◽  
Interlaminar Shear Strength ◽  
Interlaminar Shear ◽  
Scanning Electron

Inside a scanning electron microscope (SEM) chamber, we performed an in situ interlaminar shear test on a z-pinned carbon fiber-reinforced aluminum matrix composite (Cf/Al) fabricated by the pressure the infiltration method to understand its failure mechanism. Experiments show that introducing a stainless-steel z-pin increases the interlaminar shear strength of Cf/Al composite by 148%. The increase in interlaminar shear strength is attributed to the high strength of the stainless-steel z-pin and the strong bonding between the z-pin and the matrix. When the z-pin/matrix interface failed, the z-pin can still experience large shear deformation, thereby enhancing delamination resistance. The failure mechanism of composite includes interfacial debonding, aluminum plough, z-pin shear deformation, frictional sliding, and fracture. These results in this study will help us understand the interlaminar strengthening mechanism of z-pins in the delamination of metal matrix composites.

scholarly journals Modification of Renewable Cardanol onto Carbon Fiber for the Improved Interfacial Properties of Advanced Polymer Composites

Polymers ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 45 ◽  
Author(s):  
Yawen Zheng ◽  
Lei Chen ◽  
Xiaoyun Wang ◽  
Guangshun Wu
Keyword(s):  
Carbon Fiber ◽  
Photoelectron Spectroscopy ◽  
In Situ Polymerization ◽  
Hydroxyl Groups ◽  
Matrix Interface ◽  
The Matrix ◽  
Fiber Matrix Interface ◽  
Fiber Matrix ◽  
Interlaminar Shear

A facile in situ polymerization was developed for grafting renewable cardanol onto the carbon fiber (CF) surfaces to strengthen the fiber–matrix interface. CFs were chemically modified with hydroxyl groups by using an aryl diazonium reaction, and then copolymerized in situ with hexachlorocyclotriphosphazene (HCCP) and cardanol to build cardanol-modified fibers (CF-cardanol). The cardanol molecules were successfully introduced, as confirmed using Raman spectra and X-ray photoelectron spectroscopy (XPS); the cardanol molecules were found to increase the surface roughness, energy, interfacial wettability, and activity with the matrix resin. As a result, the interlaminar shear strength (ILSS) of CF-cardanol composites increased from 48.2 to 68.13 MPa. In addition, the anti-hydrothermal ageing properties of the modified composites were significantly increased. The reinforcing mechanisms of the fiber–matrix interface were also studied.

scholarly journals THE TREATMENT EFFECT IN A MICROWAVE ELECTROMAGNETIC FIELD TO CHANGE THE FLEXURAL STRENGTH OF STRUCTURAL ELEMENTS OF THE CURED CARBON-FIBER COMPOSITES UNDER THE INFLUENCE OF ENVIRONMENTAL FACTORS

2020 ◽  
pp. 20-22
Author(s):  
I. Zlobina ◽  
N. Bekrenev ◽  
I. Katsuba
Keyword(s):  
Electromagnetic Field ◽  
Carbon Fiber ◽  
Environmental Factors ◽  
Bending Strength ◽  
Climatic Factors ◽  
Fiber Composites ◽  
Carbon Fiber Composites ◽  
Structural Elements ◽  
Comparative Tests ◽  
Three Point Bending

The article describes the results of comparative tests for three-point bending of carbon fiber samples processed in a microwave electromagnetic field after being exposed to environmental factors for 3 months. It is shown that the influence of external climatic factors leads to a decrease in the bending strength of control and experimental samples by 3.7% and 1.4%, respectively. At the same time, the strength of the test samples increases by 8% in comparison with the control ones.

In-Situ TEM Observations of Surface Roughening and Defect Formation in Lattice Mismatched Heteroepitaxial Thin Films

1997 ◽  
Vol 505 ◽  
Author(s):  
Cengiz S. Ozkan ◽  
William D. Nix ◽  
Huajian Gao
Keyword(s):  
Thin Films ◽  
Defect Formation ◽  
High Vacuum ◽  
Surface Roughening ◽  
In Situ Tem ◽  
Thick Sample ◽  
Transmission Electron ◽  
Sample Preparation Procedure ◽  
Kinetics Of

ABSTRACTThis paper focuses on in-situ transmission electron microscopy observations of surface roughening and defect formation in heteroepitaxial Sil−xGex thin films. Annealing experiments have been carried out in-situ in the microscope under a high vacuum environment. We comment on the sample preparation procedure for in-situ TEM experiments and explain the importance of having a sufficiently thick sample to have the stress state in the film unaltered. Experimental results of in-situ surface roughening are presented for suberitically and supercritically thick Sil−xGex films. We found that, in a vacuum environment, the kinetics of surface roughening and the resulting surface morphology are much different than in a hydrogen environment.

In situ study of electron beam-induced chemical vapor deposition of Au in an environmental TEM

1995 ◽  
Vol 53 ◽  
pp. 256-257
Author(s):  
J. Drucker ◽  
R. Sharma ◽  
J. Kouvetakis ◽  
K.H.J. Weiss
Keyword(s):  
Electron Beam ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Quantum Effect ◽  
Line Drawing ◽  
Chemical Vapor ◽  
Environmental Cell ◽  
Engineering Changes ◽  
Kinetics Of

Patterning of metals is a key element in the fabrication of integrated microelectronics. For circuit repair and engineering changes constructive lithography, writing techniques, based on electron, ion or photon beam-induced decomposition of precursor molecule and its deposition on top of a structure have gained wide acceptance Recently, scanning probe techniques have been used for line drawing and wire growth of W on a silicon substrate for quantum effect devices. The kinetics of electron beam induced W deposition from WF6 gas has been studied by adsorbing the gas on SiO2 surface and measuring the growth in a TEM for various exposure times. Our environmental cell allows us to control not only electron exposure time but also the gas pressure flow and the temperature. We have studied the growth kinetics of Au Chemical vapor deposition (CVD), in situ, at different temperatures with/without the electron beam on highly clean Si surfaces in an environmental cell fitted inside a TEM column.

In situ observation of the martensitic transformation in (Mg,Y)-PSZ

1986 ◽  
Vol 44 ◽  
pp. 500-501
Author(s):  
R-R. Lee
Keyword(s):  
Martensitic Transformation ◽  
High Strength ◽  
Nucleation And Growth ◽  
In Situ Observation ◽  
Considerable Potential ◽  
Transmission Electron ◽  
Structural Applications ◽  
Applied Stresses ◽  
Kinetics Of

Partially-stabilized ZrO2 (PSZ) ceramics have considerable potential for advanced structural applications because of their high strength and toughness. These properties derive from small tetragonal ZrO2 (t-ZrO2) precipitates in a cubic (c) ZrO2 matrix, which transform martensitically to monoclinic (m) symmetry under applied stresses. The kinetics of the martensitic transformation is believed to be nucleation controlled and the nucleation is always stress induced. In situ observation of the martensitic transformation using transmission electron microscopy provides considerable information about the nucleation and growth aspects of the transformation.

Growth kinetics of Al2Cu in an Al-1.5Cu thin film by in Situ TEM

1993 ◽  
Vol 51 ◽  
pp. 1172-1173
Author(s):  
M. Park ◽  
S.J. Krause ◽  
S.R. Wilson
Keyword(s):  
Thin Film ◽  
In Situ Tem ◽  
Collector Plate ◽  
Transmission Electron ◽  
Device Processing ◽  
Corrosion Susceptibility ◽  
Precipitation Phenomena ◽  
Semiconductor Chips ◽  
Kinetics Of

Cu alloying in Al interconnection lines on semiconductor chips improves their resistance to electromigration and hillock growth. Excess Cu in Al can result in the formation of Cu-rich Al2Cu (θ) precipitates. These precipitates can significantly increase corrosion susceptibility due to the galvanic action between the θ-phase and the adjacent Cu-depleted matrix. The size and distribution of the θ-phase are also closely related to the film susceptibility to electromigration voiding. Thus, an important issue is the precipitation phenomena which occur during thermal device processing steps. In bulk alloys, it was found that the θ precipitates can grow via the grain boundary “collector plate mechanism” at rates far greater than allowed by volume diffusion. In a thin film, however, one might expect that the growth rate of a θ precipitate might be altered by interfacial diffusion. In this work, we report on the growth (lengthening) kinetics of the θ-phase in Al-Cu thin films as examined by in-situ isothermal aging in transmission electron microscopy (TEM).

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