Micromilling Responses of Hierarchical Graphene Composites

2015 ◽  
Vol 137 (1) ◽  
Author(s):  
Bryan Chu ◽  
Johnson Samuel ◽  
Nikhil Koratkar
Keyword(s):  
Electron Microscopy ◽  
Surface Roughness ◽  
Tool Wear ◽  
Glass Fiber ◽  
Fiber Composite ◽  
Glass Fibers ◽  
Two Phase ◽  
Graphene Composite ◽  
The Matrix ◽  
Phase Glass

The objective of this research is to examine the micromachining responses of a hierarchical three-phase composite made up of microscale glass fibers that are held together by an epoxy matrix, laden with nanoscale graphene platelets (GPL). To this end, micromilling experiments are performed on both a hierarchical graphene composite as well as on a baseline two-phase glass fiber composite without the graphene additive. The composite microstructure is characterized using transmission electron microscopy (TEM) and scanning electron microscopy (SEM) methods. Tool wear, chip morphology, cutting force, surface roughness, and fiber–matrix debonding are employed as machinability measures. In general, the tool wear, cutting forces, surface roughness, and extent of debonding are all seen to be lower for the hierarchical graphene composite. These improvements are attributed to the fact that GPL improve the thermal conductivity of the matrix, provide lubrication at the tool–chip interface, and also improve the interface strength between the glass fibers and the matrix. Thus, the addition of graphene to a conventional two-phase glass fiber epoxy composite is seen to improve not only its mechanical properties but also its machinability.

Micro-Milling Responses of Hierarchical Graphene Composites

2013 ◽  
Author(s):  
Bryan Chu ◽  
Johnson Samuel ◽  
Nikhil Koratkar
Keyword(s):  
Electron Microscopy ◽  
Surface Roughness ◽  
Tool Wear ◽  
Glass Fiber ◽  
Glass Fibers ◽  
Micro Milling ◽  
Two Phase ◽  
Graphene Composite ◽  
The Matrix ◽  
Phase Glass

The objective of this research is to examine the micro-machining responses of a hierarchical three-phase composite made up of micro-scale glass fibers that are held together by an epoxy matrix laden with nano-scale graphene platelets. To this end, micro-milling experiments are performed on both the hierarchical graphene composite as well as on a baseline two-phase glass fiber composite without the graphene additive. The composite microstructure is characterized using transmission electron microscopy and scanning electron microscopy methods. Tool wear, chip morphology, cutting force, surface roughness and delamination are employed as machinability measures. In general, the tool wear, cutting forces, surface roughness and extent of delamination are all seen to be lower for the hierarchical graphene composite. These improvements are attributed to the fact that graphene platelets improve the thermal conductivity of the matrix, provide lubrication at the tool-chip interface and also improve the interface strength between the glass fibers and the matrix. Thus, the addition of graphene to a conventional two-phase glass fiber epoxy composite is seen to not only improve its mechanical properties but also its machinability.

Using crystallographic symmetry in diffraction and contrast analysis

1989 ◽  
Vol 47 ◽  
pp. 504-505
Author(s):  
U. Dahmen ◽  
K.H. Westmacott
Keyword(s):  
Electron Microscopy ◽  
High Symmetry ◽  
Two Phase ◽  
Tem Analysis ◽  
Crystallographic Symmetry ◽  
The Matrix ◽  
Contrast Analysis ◽  
Practical Tool ◽  
Convergent Beam ◽  
Beam Diffraction

Despite the increased use of convergent beam diffraction, symmetry concepts in their more general form are not commonly applied as a practical tool in electron microscopy. Crystal symmetry provides an abundance of information that can be used to facilitate and improve the TEM analysis of crystalline solids. This paper draws attention to some aspects of symmetry that can be put to practical use in the analysis of structures and morphologies of two-phase materials.It has been shown that the symmetry of the matrix that relates different variants of a precipitate can be used to determine the axis of needle- or lath-shaped precipitates or the habit plane of plate-shaped precipitates. By tilting to a special high symmetry orientation of the matrix and by measuring angles between symmetry-related variants of the precipitate it is possible to find their habit from a single micrograph.

scholarly journals Microstructure and fracture mode of unalloyed dual phase austempered ductile iron

2021 ◽  
pp. 27-27
Author(s):  
Petar Janjatovic ◽  
Cekic Eric ◽  
Dragan Rajnovic ◽  
Sebastian Balos ◽  
Vencislav Grabulov ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Ductile Iron ◽  
Tensile Testing ◽  
Dual Phase ◽  
Material Microstructure ◽  
Two Phase ◽  
Major Disadvantage ◽  
The Matrix ◽  
Type Of Fracture ◽  
Scanning Electron

Dual phase ADI material microstructure consists of different amounts and morphologies of ausferrite and free ferrite, obtained by subjecting ductile iron to specific heat treatment. As such, its strength is lower compared to comparable ADI materials, but exhibiting a higher ductility, the major disadvantage of ADI. In the current study, an unalloyed ductile iron was intercritical austenitised in two-phase regions (?+?) at four temperatures from 840 to 780?C for 2 hours and austempered at 400?C for 1 hour to obtain dual phase ADI with different percentages of free ferrite and ausferrite. Metallographic and fracture studies were performed by light and scanning electron microscopy, respectively. Microscopy results were correlated to tensile testing results. The results indicated that, as the amount of ausferrite present in the matrix increases, higher values of strength and lower ductility are obtained. The fracture surfaces of dual phase ADI microstructures with 22.8% of ausferrite in their matrix have regions of quasi-cleavage fracture around last-to-freeze zones, related to the presence of ausferrite in those areas. The specimens with the highest values of ausferrite of 86.8% among the dual phase microstructure have a dominant quasi-cleavage type of fracture.

Ultrafine Glass Fibers Produced by Centrifugal-Spinneret-Blow Process

2012 ◽  
Vol 628 ◽  
pp. 27-32 ◽  
Author(s):  
Zhou Chen ◽  
Xue Yu Cheng ◽  
Zhao Feng Chen ◽  
Juan Zhang ◽  
Yong Yang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thermal Conductivity ◽  
Glass Fiber ◽  
Fiber Diameter ◽  
Raw Materials ◽  
Glass Fibers ◽  
Optical Microscope ◽  
Fiber Sample ◽  
Heat Flow Meter ◽  
Scanning Electron

In this paper, glass fibers were prepared by centrifugal-spinneret-blow(CSB)process. The diameter and microstructure of glass fibers have been investigated by scanning electron microscopy(SEM)and vertical optical microscope(VOM).The thermal conductivity and the thickness of glass fiber samples were determined by heat flow meter thermal conductivity instrumentation.The results indicated that the diameter of glass fibers prepared by CSB process can reach the ultrafine grade by adjusting the ratio of raw materials and process parameters.The thermal conductivity of glass fiber sample was 0.0298W/(m·K)when the diameter was 3μm and the density was 62kg/m3.The thermal conductivity of glass fiber sample decreased with the reduction of fiber diameter when the density of glass fiber sample is constant.

scholarly journals Formation mechanisms and atomic configurations of nitride phases at the interface of aluminum nitride and titanium

2008 ◽  
Vol 23 (8) ◽  
pp. 2221-2228 ◽  
Author(s):  
Chia-Hsiang Chiu ◽  
Chien-Cheng Lin
Keyword(s):  
Electron Microscopy ◽  
Aluminum Nitride ◽  
Analytical Electron Microscopy ◽  
Phase Region ◽  
Titanium Foil ◽  
Formation Mechanisms ◽  
Two Phase ◽  
Analytical Electron ◽  
The Matrix ◽  
Lamellar Layer

Aluminum nitride was bonded with a titanium foil at 1400 °C for up to 1 h in Ar. The AlN/Ti interfacial reactions were investigated using analytical electron microscopy. Reaction layers, consisting of δ-TiN, τ2-Ti2AlN, γ-TiAl, α2-Ti3Al, a two-phase region (α2-Ti3Al + α-Ti), and α-Ti (Al, N) solid solution, were observed after annealing at 1400 °C for 0.1 h. Among these phases, the α2-Ti3Al and (α2-Ti3Al + α-Ti) were formed during cooling. Further diffusion of N atoms into the reaction zone precipitates a chopped fiber-like α2-Ti2AlN in the matrix of γ-TiAl, with [110]γ−TiAl//[11¯20]τ2−Ti2AlN and (1¯1¯1)γ−TiAl//(1¯10¯3)τ2−Ti2AlN, by substituting N atoms for one-half Al atoms after annealing at 1400 °C for 1 h. The released Al atoms, due to the precipitation of τ2-Ti2AlN, resulted in an ordered Al-rich γ-TiAl or Ti3Al5. Furthermore, the α-Ti (Al, N) was nitridized into a lamellar layer (δ-TiN + α-Ti) with [110]δ−TiN//[11¯20]α−Ti and (111)δ−TiN//(0001)α−Ti.

scholarly journals Propargylated Novolac Resins for Solvent-Free Technology for High-Performance Composites

2018 ◽  
Vol 20 (2) ◽  
pp. 125
Author(s):  
D. Kalugin ◽  
S. Nechausov ◽  
A. Galiguzov ◽  
A. Malakho ◽  
V. Lepin ◽  
...  
Keyword(s):  
Bisphenol A ◽  
Glass Fiber ◽  
High Performance ◽  
Phenolic Resin ◽  
Fiber Composite ◽  
Glass Fibers ◽  
Sem Analysis ◽  
Solvent Free ◽  
Glass Fiber Composite ◽  
Novolac Phenolic Resin

Propargyl substituted novolac phenolic resin diluted with unsaturated bisphenol-A ethers was used for glass fiber solvent-free impregnation for the formation of high-performance composites. The addition of 20% mass of diallyl (DAEBA) or dipropargyl (DPEBA) bisphenol-A to propargyl substituted novolac phenolic resin resulted in viscosity drop from 2000 mPa∙s to 400‒500 mPa∙s at 140 °C. This proved to be enough to achieve complete impregnation of the twisted glass fibers, as illustrated by SEM analysis. This improvement in impregnation was shown to result in increasing both flexural strength and modulus of the unidirectional glass fiber composite material approximately with a factor of two compared to the composite impregnated with resin without bisphenol-A ethers. DPEBA was shown to be more suitable for high-temperate applications since its addition does not seem to result in a decrease of the heat deflection temperature (HDT).

Preliminary Study of Polypropylene/Sawdust Green Composite

2012 ◽  
Vol 557-559 ◽  
pp. 334-337 ◽  
Author(s):  
Ching Wen Lou ◽  
Ching Wen Lin ◽  
Chen Hung Huang ◽  
Ting Ting Li ◽  
Jin Mao Chen ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Glass Fiber ◽  
Bending Strength ◽  
Fiber Composite ◽  
Glass Fibers ◽  
Bending Test ◽  
Green Composite ◽  
Plastic Composite ◽  
Glass Fiber Composite ◽  
Injection Molded

In this study, sawdust and polypropylene (PP) are melt-blended and injection-molded to form the wood-plastic composite (WPC).The WPC is then tested in terms of mechanical properties and compared with control groups of pure PP plate and PP/glass fiber (PP/GF) composite. In the tensile test, the WPC displays a tensile strength of 25-27 MPa, regardless of whether the sawdust content is 5, 10, or 15 wt%. Pure PP composite has a tensile strength of 30 MPa; PP/GF composite with 15 wt% glass fibers has a tensile strength of 57 MPa. In the bending test, the WPC displays a flexural strength of 44-45 MPa as the sawdust content does not influence the bending strength. PP/glass fiber composite yields a bending strength of 85 MPa when the content of glass fiber is 15 wt%. WPC is 5% lighter than PP/glass fiber composite.

scholarly journals The Mechanical Properties of High Strength Reinforced Cured-in-Place Pipe (CIPP) Liner Composites for Urban Water Infrastructure Rehabilitation

Water ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 983 ◽  
Author(s):  
Hyun Ji ◽  
Sung Yoo ◽  
Jonghoon Kim ◽  
Dan Koo
Keyword(s):  
Mechanical Properties ◽  
Glass Fiber ◽  
Urban Areas ◽  
Structural Integrity ◽  
Fiber Composite ◽  
Unsaturated Polyester ◽  
Glass Fibers ◽  
Flexural Modulus ◽  
High Strength ◽  
Water Infrastructure

Most urban areas in the world have water infrastructure systems, including the buried sewer and water pipelines, which are assessed as in need of extensive rehabilitation. Deterioration by many other factors affects structural integrity. Trenchless technologies such as Cured-in-Place Pipe (CIPP) are now applied in numerous projects while minimizing disturbance in an urban environment. The main purpose of this study is to develop a high strength CIPP material using various composite materials (e.g., glass fiber, carbon fiber, polyester felt, unsaturated polyester resin, and others). Composite samples were made of the materials and tested using three-point bend apparatus to find mechanical properties, which include the flexural modulus, strength, and deflection. A composite combination with glass fibers with thin felt layers shows the best results in mechanical properties. Flexural modulus is a key factor for CIPP liner thickness design. Glass fiber composite yields between four and nine times higher values than the minimum value specified in the American Society for Testing and Materials (ASTM) F1216. This study provides a fundamental baseline for high strength CIPP liners that are capable of using conventional curing technologies.

scholarly journals Durability and Physical Properties of Glass Fiber Reinforced Concrete Subjected to Elevated Temperatures

2019 ◽  
Vol 8 (11) ◽  
pp. 3845-3848
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Reinforced Concrete ◽  
Glass Fiber ◽  
Elevated Temperatures ◽  
Glass Fibers ◽  
Fiber Reinforced Concrete ◽  
Fiber Reinforced ◽  
Glass Fiber Reinforced ◽  
The Matrix

Addition of glass fibers into concrete significantly modifies its tensile strength. The fibers are placed at desired locations and orientations by the matrix surrounding it, thereby making the fibers as principal load carrying members and also protecting them from environmental damage. Glass fibers provide resistance to high temperature, and the ease of incorporating them into the matrix either in continuous or discontinuous lengths. In this work, carbonation test representing the durability of Glass Fiber Reinforced Concrete (GFRC) was carried out, and then experimental program determines the properties like compressive strength, split tensile strength and flexural strength of GFRC for 7 days and 28 days of curing, with percentage of fibers in ratios 0.5%, 1%, 1.5%, 2% and performance of GFRC at elevated temperatures of 300°c, 500°c, 700°c, 1000°c are compared with conventional concrete. The results depict that, the residual compressive strength capacity of GFRC is greater than unreinforced concrete both at elevated and normal temperatures.

Study of Corrosion Damage of Glass Fibers in Textile Fiberglass Reinforcement under Expositions Simulating Concrete Environment

2018 ◽  
Vol 272 ◽  
pp. 189-196
Author(s):  
Tomáš Bittner ◽  
Petr Pokorný ◽  
Petr Bouška ◽  
Šárka Nenadálová
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Glass Fiber ◽  
High Stability ◽  
Pore Solution ◽  
Glass Fibers ◽  
Corrosion Damage ◽  
Organic Coating ◽  
Ft Ir ◽  
Scanning Electron

The main point of this paper is to assess the level of corrosion damage of the composite textile fiberglass reinforcement in environments that simulate the concrete pore solution by the techniques of FT-IR (Fourier transform infrared spectroscopy), SEM (scanning electron microscopy) as well as EDS (scanning electron microscopy). Effect of corrosion on the tensile strength segmented textile glass fiber was tested and also it was investigated specific type of protective organic coating on glass fiber. The results express the evidence of local corrosion damage on the examined samples just at pH 13.5, and on the contrary high stability in the environment simulating carbonated concrete and concrete contaminated by chloride anions. The thesis also points on the unevenness of the excluded protective organic coating with localized porosity which relates to the above mentioned corrosion damage.

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