The Strange Case of Compacted Graphite Iron: A Remarkable Option with Unique Material Properties or an Unusable Alloy?

2017 ◽  
Vol 754 ◽  
pp. 67-70
Author(s):  
Slobodna Mitrovic ◽  
Emanuele Savini ◽  
Dragan Dzunic
Keyword(s):  
Material Properties ◽  
Compacted Graphite Iron ◽  
Cast Irons ◽  
Practical Applications ◽  
Compacted Graphite ◽  
Wide Range ◽  
Unique Material ◽  
Material Choice ◽  
Strength And Stiffness ◽  
Grey Iron

The Compacted Graphite Iron (CGI) represents an example of material with remarkable and unexplored properties, especially in terms of resistance and machinability. With better strength and stiffness than several cast irons, as Grey Iron, and better castability, machinability and thermal conductivity than others, as Ductile Irons, this alloy would be, at least theoretically, the perfect material choice for a wide range of practical applications. Nevertheless, discovered more than 50 years ago, it has failed to establish itself in a definitive way. This review intends to highlight benefits and limits in choosing CGI in casting.

scholarly journals Synthesis, Properties, and Selected Technical Applications of Magnesium Oxide Nanoparticles: A Review

2021 ◽  
Vol 22 (23) ◽  
pp. 12752
Author(s):  
Jaroslav Hornak
Keyword(s):  
Magnesium Oxide ◽  
Material Properties ◽  
Biotechnological Applications ◽  
Reaction Conditions ◽  
Environmental Friendliness ◽  
Suitable Candidate ◽  
Magnesium Oxide Nanoparticles ◽  
Wide Range ◽  
Unique Material ◽  
Synthesis Properties

In the last few decades, there has been a trend involving the use of nanoscale fillers in a variety of applications. Significant improvements have been achieved in the areas of their preparation and further applications (e.g., in industry, agriculture, and medicine). One of these promising materials is magnesium oxide (MgO), the unique properties of which make it a suitable candidate for use in a wide range of applications. Generally, MgO is a white, hygroscopic solid mineral, and its lattice consists of Mg2+ ions and O2− ions. Nanostructured MgO can be prepared through different chemical (bottom-up approach) or physical (top-down approach) routes. The required resultant properties (e.g., bandgap, crystallite size, and shape) can be achieved depending on the reaction conditions, basic starting materials, or their concentrations. In addition to its unique material properties, MgO is also potentially of interest due to its nontoxicity and environmental friendliness, which allow it to be widely used in medicine and biotechnological applications.

scholarly journals Synthesis, Characterization, and Applications of ZnO Nanowires

2012 ◽  
Vol 2012 ◽  
pp. 1-22 ◽  
Author(s):  
Yangyang Zhang ◽  
Manoj K. Ram ◽  
Elias K. Stefanakos ◽  
D. Yogi Goswami
Keyword(s):  
Environmental Protection ◽  
Material Properties ◽  
Zno Nanowires ◽  
Synthesis Methods ◽  
Special Focus ◽  
Wide Range ◽  
Unique Material ◽  
Photocatalytic Applications

ZnO nanowires (or nanorods) have been widely studied due to their unique material properties and remarkable performance in electronics, optics, and photonics. Recently, photocatalytic applications of ZnO nanowires are of increased interest in environmental protection applications. This paper presents a review of the current research of ZnO nanowires (or nanorods) with special focus on photocatalysis. We have reviewed the semiconducting photocatalysts and discussed a variety of synthesis methods of ZnO nanowires and their corresponding effectiveness in photocatalysis. We have also presented the characterization of ZnO nanowires from the literature and from our own measurements. Finally, a wide range of uses of ZnO nanowires in various applications is highlighted in this paper.

Effects of Water Exposure on the Mechanical Properties of Early Artists' Acrylic Paints

2004 ◽  
Vol 852 ◽  
Author(s):  
Eric Hagan ◽  
Alison Murray
Keyword(s):  
Mechanical Properties ◽  
Material Properties ◽  
Water Soluble ◽  
Secant Modulus ◽  
Water Exposure ◽  
Wide Range ◽  
Before And After ◽  
Strength And Stiffness ◽  
Paint Films ◽  
Acrylic Paints

ABSTRACTThe mechanical properties of early artist's acrylic paints were investigated under controlled aqueous additive leaching for the purpose of identifying changes caused by cleaning paintings with water. Strength and stiffness values were obtained using a tensiometer to collect stress-strain curves of paint films. The results were compared to those from similar experiments in which paint films were tested under various age, temperature, and relative humidity (RH) values. Strength and stiffness both increased with decreased temperature, decreased RH, increased age, and increased additive removal. The most significant impact on mechanical properties was caused by lowering temperature to the Tg region around 5°C. Dramatic changes in properties were caused by RH fluctuations; however, the magnitudes were negligible in comparison to those induced by low temperature. Removal of water-soluble additives produced a uniform increase in tensile strength and secant modulus at all RH values. The films were equally responsive to fluctuations in RH before and after additive leaching. In comparing the material properties across a wide range of conditions it is evident that the acrylic paints in this study were not significantly altered by the amount of water exposure involved in cleaning paintings.

scholarly journals Problems of using computer control of vermicular graphite in the microstructure of cast iron

2019 ◽  
Author(s):  
Ирина Шаехова ◽  
Irina Shaehova ◽  
Алексей Панов ◽  
Aleksey Panov ◽  
Надежда Дегтярёва ◽  
...  
Keyword(s):  
Materials Science ◽  
Computer Control ◽  
Automatic Identification ◽  
Calculation Error ◽  
Compacted Graphite Iron ◽  
Graphite Inclusion ◽  
Automatic Calculation ◽  
Compacted Graphite ◽  
Wide Range ◽  
Necessary Truth

In recent decades, there has been an increase in industrial interest in compacted graphite iron, which has a very wide range of properties more depended on the graphite form. The same time, to date, there are no methods for controlling graphite in the microstructure of CGI necessary truth. In the present work, the automatic calculation error of the fraction of vermicular graphite is estimated, which is associated with the automatic identification error of the type of graphite inclusion. It is shown that automatic calculation without the metallographist increases accuracy in comparison with GOST 3443-87, but its error remains not acceptably high for materials science tasks and requires further improvement.

Perfectly Elastic Axisymmetric Sinusoidal Surface Asperity Contact

2016 ◽  
Vol 138 (3) ◽  
Author(s):  
S. Saha ◽  
Y. Xu ◽  
R. L. Jackson
Keyword(s):  
Contact Area ◽  
Material Properties ◽  
Point Contact ◽  
Asperity Contact ◽  
Hertz Contact ◽  
Practical Applications ◽  
Wide Range ◽  
Complex Models ◽  
Complete Contact ◽  
Sinusoidal Surface

This work presents a finite element (FE) study of a perfectly elastic axisymmetric sinusoidal-shaped asperity in contact with a rigid flat for different amplitude to wavelength ratios and a wide range of material properties. This includes characterizing the pressure required to cause complete contact between the surfaces. Complete contact is defined as when there is no gap remaining between two contacting surfaces. The model is designed in such a way that its axisymmetric and interaction with the adjacent asperities are considered by the effect of geometry at the base of the asperity. The numerical results are compared to the model of curved point contact for the perfectly elastic case (known as Hertz contact) and Westergaard's solution. Once properly normalized, the nondimensional contact area does not vary with nondimensional load. The critical pressure required to cause complete contact is found. The results are also curve fitted to provide an expression for the contact area as a function of load over a wide range of cases for use in practical applications, such as to predict contact resistance. This could be a stepping stone to more complex models.

scholarly journals Hydrophobic–hydrophilic dichotomy of the butterfly proboscis

2013 ◽  
Vol 10 (85) ◽  
pp. 20130336 ◽  
Author(s):  
Matthew S. Lehnert ◽  
Daria Monaenkova ◽  
Taras Andrukh ◽  
Charles E. Beard ◽  
Peter H. Adler ◽  
...  
Keyword(s):  
Material Properties ◽  
Structural Modification ◽  
Structural Changes ◽  
External Surface ◽  
Viscous Liquids ◽  
Fluid Uptake ◽  
Wide Range ◽  
Unique Material ◽  
Sap Feeding ◽  
Cuticular Structures

Mouthparts of fluid-feeding insects have unique material properties with no human-engineered analogue: the feeding devices acquire sticky and viscous liquids while remaining clean. We discovered that the external surface of the butterfly proboscis has a sharp boundary separating a hydrophilic drinking region and a hydrophobic non-drinking region. The structural arrangement of the proboscis provides the basis for the wetting dichotomy. Theoretical and experimental analyses show that fluid uptake is associated with enlargement of hydrophilic cuticular structures, the legulae, which link the two halves of the proboscis together. We also show that an elliptical proboscis produces a higher external meniscus than does a cylindrical proboscis of the same circumference. Fluid uptake is additionally facilitated in sap-feeding butterflies that have a proboscis with enlarged chemosensory structures forming a brush near the tip. This structural modification of the proboscis enables sap feeders to exploit films of liquid more efficiently. Structural changes along the proboscis, including increased legular width and presence of a brush-like tip, occur in a wide range of species, suggesting that a wetting dichotomy is widespread in the Lepidoptera.

scholarly journals Assessment of crystallographic influence on material properties of calcite brachiopods

2008 ◽  
Vol 72 (2) ◽  
pp. 563-568 ◽  
Author(s):  
A. Pérez-Huerta ◽  
M. Cusack ◽  
W. Zhu
Keyword(s):  
Material Properties ◽  
Materials Science ◽  
High Spatial Resolution ◽  
Electron Backscatter Diffraction ◽  
Longitudinal Section ◽  
Nano Indentation ◽  
Wide Range ◽  
Unique Material ◽  
Backscatter Diffraction ◽  
Insufficient Knowledge

AbstractCalcium carbonate biominerals are frequently analysed in materials science due to their abundance, diversity and unique material properties. Aragonite nacre is intensively studied, but less information is available about the material properties of biogenic calcite, despite its occurrence in a wide range of structures in different organisms. In particular, there is insufficient knowledge about how preferential crystallographic orientations influence these material properties. Here, we study the influence of crystallography on material properties in calcite semi-nacre and fibres of brachiopod shells using nanoindentation and electron backscatter diffraction (EBSD). The nano-indentation results show that calcite semi-nacre is a harder and stiffer (H ≈ 3—5 GPa; E = 50–85 GPa) biomineral structure than calcite fibres (H = 0.4—3 GPa; E = 30—60 GPa). The integration of EBSD to these studies has revealed a relationship between the crystallography and material properties at high spatial resolution for calcite semi-nacre. The presence of crystals with the c-axis perpendicular to the plane-of-view in longitudinal section increases hardness and stiffness. The present study determines how nano-indentation and EBSD can be combined to provide a detailed understanding of biomineral structures and their analysis for application in materials science.

Effect of Alloying Elements on Graphite Morphology in CGI

2010 ◽  
Vol 649 ◽  
pp. 171-176 ◽  
Author(s):  
Martin Selin ◽  
Daniel Holmgren ◽  
Ingvar L. Svensson
Keyword(s):  
Thermal Conductivity ◽  
Material Properties ◽  
Alloying Elements ◽  
Alloying Element ◽  
Cast Irons ◽  
Compacted Graphite ◽  
Alloying Additions ◽  
Graphite Morphology ◽  
Shape And Size ◽  
Effect Of Alloying

Understanding how alloying elements and amounts affect the shape and size of graphite in compacted graphite cast irons could be of great importance. Some important material properties that are affected by the graphite shape are tensile strength and thermal conductivity. Knowing the effect of alloying additions could be of assistance when trying to optimise material for a specific application. In order to determine how graphite changes depending on alloying additions the microstructure of nineteen CGI materials were investigated. All melts were based on one chemical composition and alloying elements were added to obtain melts with variation in magnesium, silicon, copper, tin, chromium and molybdenum. Some of the more important microstructure features that were analysed are the amount and size of different graphite particles. The result from this analysis should give an indication on what features each alloying element affect and how these features varies with alloying amount.

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