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Topic: Eutectoid


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In the News (Thu 23 May 19)

  
  JAIC 1994, Volume 33, Number 1, Article 1 (pp. 1 to 23)
19), an area of eutectoid is seen isolated within the corrosion layer, showing that the copper-rich alpha phase of the bronze is preferentially corroded with preservation of eutectoid relicts.
The alpha grains are equiaxial and bordered by eutectoid fringes.
One surprising observation was the existence of metallic remnants of alpha + delta phase eutectoid at the outer extremity of the pustule, a considerable distance from the metallic core of the Togati, and 1 mm above the tin oxide patina.
aic.stanford.edu /jaic/articles/jaic33-01-001_3.html   (1636 words)

  
 Molybdenum disilicide composites - Patent 6197247
3 is a scanning electron image of the microstructure of an eutectoid matrix region of a composite made in accordance with the invention method.
The invention method comprises combining a major portion of molybdenum disilicide powder with a minor portion of silicon nitride powder to form a mixture which is then combined with a minor portion of aluminum powder with alumina coating on the aluminum particles.
The eutectoid composites of this invention would be useful for structural components or heating elements because of high temperature resistance, high temperature electrical and thermal conductivity, and oxidation resistance properties.
www.freepatentsonline.com /6197247.html   (5418 words)

  
 Chapter 9. Phase Diagrams
The eutectoid (eutectic-like) reaction is similar to the eutectic reaction but occurs from one solid phase to two new solid phases.
The eutectoid composition of austenite is 0.76 wt %.
Since reactions below the eutectoid temperature are in the solid phase, the equilibrium is not achieved by usual cooling from austenite.
www.virginia.edu /bohr/mse209/chapter9.htm   (1145 words)

  
 Project Glossary
Eutectoid: A eutectoid system occurs when a single-phase solid transforms directly to a two-phase solid.
Face-centered: A structure in which there is an atom at the corner of each unit cell and one in the center of each face, but no atom in the center of the cube.
Pearlite: A lamellar mixture of ferrite and carbide formed by decomposing austenite of eutectoid composition.
www.sv.vt.edu /classes/MSE2094_NoteBook/96ClassProj/gloss.html   (865 words)

  
 PhD THESES - PHYSICAL AND PROCESS METALLURGY - 1998/99
Eutectoid decomposition in steels can result in either a lamellar (pearlite) or non-lamellar (bainite) microconstituent.
The lamellar microconstituent formed from both plates of a(Ti) and allotriomorphs of Ti Co. Heat treatment at progressively higher undercooling resulted in the lamellar microconstituent being increasingly replaced by a spheroidal microconstituent.
A new hypothesis has been proposed suggesting that it is not pearlite and bainite that are competing processes in Ti-X alloys, but pearlite and the formation of a (Ti) plates.
www.surrey.ac.uk /eng/research/caspie/physmet/pm00.html   (884 words)

  
 Arius Eickert Eutectoid Region of Steel Technical Article
The corresponding eutectoid composition is approximately 0.77% carbon.
The eutectoid chart is important, because during the cooling process, the Fe-C eutectoid reaction involves the simultaneous formation of Ferrite and Carbide in a unique microstructure called PEARLITE.
Pearlite is a lamellar mixture or alternating layers of 88% ferrite and 12% carbide.
ariuseickert.com /ScissorTechnicalArticles/EutectoidRegionOfSteel.htm   (378 words)

  
 Solidification of steels
eutectoid (eutectic-like) to show that the reaction is in the solid state.
When the steel reaches the eutectoid temperature the remaining austenite will be of eutectoid composition and transforms into pearlite (alpha+cementite).
For example, strength increases with carbon content up to the eutectoid composition but then starts to drop as a grain-boundary network of brittle cementite is formed.
www.soton.ac.uk /~pasr1/steels.htm   (666 words)

  
 Titanium Alloys - Alpha, Beta and Alpha-Beta Alloys
Beta-eutectoid elements have restricted solubility in beta titanium and form intermetallic compounds by eutectoid decomposition of the beta phase.
Eutectoid decomposition of beta phase in the titanium-iron, titanium-chromium and titanium-manganese systems is so slow that intermetallic compound formation does not occur during normal commercial fabrication and heat treatment or during service and, therefore, for practical purposes the behaviour of iron, chromium and manganese can be likened to that of beta-isomorphous elements.
In contrast, copper and silicon form active eutectoid systems where below the eutectoid temperature the beta phase decomposes to alpha and intermetallic compounds within commercially acceptable times.
www.azom.com /details.asp?ArticleID=915   (969 words)

  
 Machinability of Gray Cast Iron
Some of the carbon dissolved in austenite during eutectic solidification must diffuse from the austenite and migrate to graphite flakes or nodules as the metal cools to the eutectoid temperature.
High cooling rates from the eutectic to the eutectoid temperature may not provide enough time for the carbon to diffuse to the graphite.
The carbon must be able, in the time available as the iron cools from the eutectic to the eutectoid temperature, to diffuse from the austenite and attach itself to the graphite flakes or nodules.
www.atlasfdry.com /machinability.htm   (941 words)

  
 Pearlite - Wikipedia, the free encyclopedia
Pearlite occurs at the eutectoid of the iron-carbon phase diagram (near the lower left).
Pearlite is a two-phased, lamellar structure composed of alternating layers of ferrite (88 wt%) and cementite (12%) that occurs in steel.
It forms by a eutectoid reaction as austenite is slowly cooled below 723°C. The eutectoid composition of Austenite is approximately 0.77% carbon [1]; steel with less carbon content will contain a corresponding proportion of relatively pure ferrite crystallites that do not participate in the eutectoid reaction and cannot transform into pearlite.
en.wikipedia.org /wiki/Pearlite   (226 words)

  
 Dispersion strengthened tri-titanium aluminum alloy (USH0000887)   (Site not responding. Last check: 2007-10-09)
A titanium alloy comprising about 15 to 25 atomic percent (a/o) aluminum, about 0.05 to 12 a/o of at least one beta eutectoid stabilizing element and about 4 to 12 a/o of at least one beta isomorphous stabilizing element, balance titanium.
The presently preferred amounts of the beta eutectoid stabilizing elements are as follows: Cu, Ni or Cr, about 4.50 to 12.0 a/o; Si, B or C, about 0.70 to 5.0 a/o; Er, Y or Ce, about 0.05 to 0.25 a/o.
The beta eutectoid element is at least one of Cu, Ni, Cr, Er, Y, Ce, Si, B or C. The beta isomorphous stabilizing element is Nb or a mixture of Nb with Ta, Mo or V, wherein the Nb can be replaced by Ta, Mo or V up to about half of the stated quantity.
www.priorartdatabase.com /IPCOM/000000882   (490 words)

  
 Eutectic point - Wikipedia, the free encyclopedia
Some inks are eutectic mixtures, allowing inkjet printers to operate at lower temperatures.
For instance, in the iron-carbon system, the austenite phase can undergo a eutectoid transformation to produce ferrite and cementite (iron carbide), often in lamellar structures such as pearlite and bainite.
This eutectoid point is at about 0.6% carbon; alloys of nearly this composition are called high-carbon steel, while those which do not undergo eutectoid transformation are termed mild steel.
en.wikipedia.org /wiki/Eutectoid   (964 words)

  
 167 Eutectoid plating
This seemed to be in reference to a co-deposition of a metal and a polymer, but I can't see what that has to do with a eutectoid reaction.
To me a eutectoid reaction is one solid solution going to two upon cooling through a set temperature (like a martensitic transformation in steel).
HELLO, Eutectoid plating may refer to a codeposition process.
www.finishing.com /0000-0199/167.shtml   (217 words)

  
 Engineering Materials – NOTES – Chapter 9 – Phase Diagrams
Eutectoid Composition:  The cooling of steel is similar to the eutectoid materials we studied earlier.
Hypoeutectoid Alloys:  These are alloys with a composition between 0.022 and 0.76 wt%C (to the left of the eutectoid).
9.32), with all common alloys lowering the C wt% of the eutectoid composition.
www.uwplatt.edu /~mirth/me3040ch9.htm   (1862 words)

  
 Monday AM Session
This was the first time the very early stages of the eutectoid reaction is continuously cooled NAB was clearly documented.
A model describing the very early stages of the eutectoid reaction in NAB was presented.
At 815°C, the eutectoid reaction was mostly discrete but became lamellar as the transformation temperature was lowered.
www.tms.org /Meetings/MW97/Program/Sessions/MA210.html   (1692 words)

  
 X Axis
It also distinguishes between Hypo Eutectoid and Hyper Eutectoid and Hypo Eutectic and Hyper Eutectic.
Below.83% C, the specimen is Hypo Eutectoid and more than.83% C, the specimen is Hyper Eutectoid.
The Y-axis of the iron-iron C Equilibrium Diagram shows temperature range from 0 to 3000 degrees Fahrenheit.
lennon.csufresno.edu /~vijay143/I5.htm   (155 words)

  
 ENGR322 Homework Set Five
Thus, all of the ALPHA phase comes from the eutectoid transformation, and appears in the microstructure as part of the pearlite.
In the second possibility, we have a HYPO-EUTECTOID alloy, in which case there is both pro-eutectoid and eutectoid ALPHA phase present.
Spheroidite has a microstructure in which the pearlitic lamellae have coalesced into spherical precipitates, once again reducing the amount of surface area between the Fe3C and the ferrite.
oregonstate.edu /instruct/engr322/Homework/Previous/S98/ENGR322HW5.html   (1107 words)

  
 Alloy, Metal Terminology (E)
Steel representing the eutectoid composition of the iron carbon system, with about 0.80% to 0.83% carbon, the eutectoid temperature being about 1333°F. Such steel in the annealed condition consists exclusively of pearlite.
Steels with less than this quota of carbon are known as hypo-eutectoid and contain free ferrite in addition to the pearlite.
The presence of certain elements, such as nickel or chromium, lowers the eutectoid carbon content.
www.metal-mart.com /Dictionary/dictlete.htm   (786 words)

  
 Teach Yourself Phase Diagrams   (Site not responding. Last check: 2007-10-09)
The eutectoid reaction describes the phase transformation of one solid into two different solids.
In the Fe-C system, there is a eutectoid point at approximately 0.8wt% C, 723°C. The phase just above the eutectoid temperature for plain carbon steels is known as austenite or gamma.
We now consider what happens as this phase is cooled through the eutectoid temperature (723°C).
www-g.eng.cam.ac.uk /mmg/teaching/typd/addenda/eutectoidreaction1.html   (98 words)

  
 I.I.C.E. Diagram for 2.0% Carbon [Dave Murov]   (Site not responding. Last check: 2007-10-09)
  The X axis distinguishes between “hypo” and “hyper” Eutectic and Eutectoid.
  Below.83% C, the specimen is Hypo Eutectoid and more than.83% C, the specimen is Hyper Eutectoid.
  The 2.0% Carbon cast iron used in this analysis is hypo eutectic and hyper eutectoid.
lennon.pub.csufresno.edu /~dtm24/IT283/iice.html   (750 words)

  
 Marine: NACE 05233: A Study of the Effects of Microstructure on the Seawater Jet Impingement Resistance of Nickel ...
When air cooled (AC), Alloy A contains more Widmanstatten proeuetectoid α and less α * than the oil quenched (OQ) specimen, as can be seen by comparing Figures 2 and 3, and as listed in Table 4.
In addition, small amounts of a eutectoid of α + κ
In Alloy A, tempering facilitates the transformation of Martensite and Bainite or α *, to a fine eutectoid of α + κ
www.copper.org /applications/marine/NACE05233/nace05233c.html   (1505 words)

  
 MMS Online   (Site not responding. Last check: 2007-10-09)
(2) An alloy having the composition indicated by the eutectoid point on an equilibrium diagram.
(3) An alloy structure of intermixed solid constituents formed by a eutectoid transformation.
Steel representing the eutectoid composition of the iron-carbon system, with about 0.80% to 0.83% carbon, the eutectoid temperature being about 1333 (degrees) F. Such steel in the annealed condition consists exclusively of pearlite.
www.alloytech.com /mmsonline/glossary/edoc.htm   (1258 words)

  
 Wednesday PM Session
Currently, railroad rails and some switch frogs are manufactured from pearlitic eutectoid carbon steel.
This steel can be hardened by on-line heat treatment in large tonnages to 400 BHN at little cost beyond that of basic rail.
Although hypereutectoid steels can match the strength and ductility properties of the eutectoid steels (both pearlitic and bainitic), it is not clear that large quantities can be manufactured at high strength levels as economically as can the eutectoid steels.
www.tms.org /Meetings/MW97/Program/Sessions/WP212.html   (1583 words)

  
 eutectoid - Dictionnaire Français-Anglais WordReference.com
We found no English translation for 'eutectoid' in our French to English Dictionary.
Or did you want to translate 'eutectoid' from English to French?
Forum discussions with the word(s) 'eutectoid' in the title:
www.wordreference.com /fren/eutectoid   (41 words)

  
 hyper eutectoid - OneLook Dictionary Search   (Site not responding. Last check: 2007-10-09)
We found one dictionary with English definitions that includes the word hyper eutectoid:
Tip: Click on the first link on a line below to go directly to a page where "hyper eutectoid" is defined.
Phrases that include hyper eutectoid: hyper eutectoid steel
www.onelook.com /?w=hyper+eutectoid   (70 words)

  
 EngNet > Engineering Dictionary > Eutectoid
The number of solids formed are the same number of components in the system.
2) An alloy having the same chemical composition indicated by the eutectoid point on a equilibrium diagram.
Credit: The SteelLog Dictionary information has been created and supplied by: All Metals & Forge
www.engnetglobal.com /tips/glossary.aspx?word=Eutectoid   (103 words)

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