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heterogeneous phase

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Series: ASM Technical Books
Publisher: ASM International
Published: 01 June 2008
DOI: 10.31399/asm.tb.emea.t52240053
EISBN: 978-1-62708-251-8
... transforming directly to the equilibrium phase, metastable transition phases can form prior to forming the final equilibrium phase. Like solidification, nucleation in solid-state reactions is almost always heterogeneous. Heterogeneous nucleation occurs at structural defects such as grain boundaries...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 March 2012
DOI: 10.31399/asm.tb.pdub.t53420015
EISBN: 978-1-62708-310-2
... of transforming directly to the equilibrium phase, metastable transition phases can form prior to forming the final equilibrium phase. Like solidification, nucleation in solid-state reactions is almost always heterogeneous. Heterogeneous nucleation occurs at structural defects such as grain...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 December 2016
DOI: 10.31399/asm.tb.ascaam.t59190001
EISBN: 978-1-62708-296-9
... preference results from a difference in the undercooling necessary to generate heterogeneous nucleation on the surface of each pre-eutectic phase, either α aluminum or silicon. The α aluminum solid solution nucleates at the silicon substrate in the liquid alloy undercooled to 25 K below equilibrium eutectic...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 January 2015
DOI: 10.31399/asm.tb.tpmpa.t54480031
EISBN: 978-1-62708-318-8
... two or more elements requires that the elements have compatible sizes, structures, and chemical characteristics. Alloys can contain one phase only; such alloys under equilibrium conditions are called homogeneous alloys. Alloys containing more than one phase are called heterogeneous or two- or...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 March 2012
DOI: 10.31399/asm.tb.pdub.t53420041
EISBN: 978-1-62708-310-2
... on a common line. In other words, each component must have the same chemical potential in the two phases, that is, for heterogeneous equilibrium: (Eq 3.49) μ A α = μ A β  and  μ B α = μ B β From Eq 3.49 it can be seen that the activities of...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 March 2012
DOI: 10.31399/asm.tb.pdub.t53420001
EISBN: 978-1-62708-310-2
... temperature would coincide at the equilibrium transformation temperature. The equilibrium states that are represented on phase diagrams are known as heterogeneous equilibria, because they refer to the coexistence of different states of matter. However, for two or more phases to attain mutual equilibrium...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 August 2018
DOI: 10.31399/asm.tb.msisep.t59220129
EISBN: 978-1-62708-259-4
.... ( Chapter 7, “Equilibrium Phases and Constituents in the Fe-C System,” section 7.6.1, “Hypo-Eutectoid Steels,” in this book) The heterogeneities in chemical composition generated by solidification—segregation—can be detected using chemical etchants, localized chemical analysis, and techniques such...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 August 2018
DOI: 10.31399/asm.tb.msisep.t59220101
EISBN: 978-1-62708-259-4
... Abstract This chapter describes the phases and constituents present in iron-carbon steels in near-equilibrium conditions. It explains how to use phase diagrams to predict and manage the development of ferrite, austenite, cementite, and pearlite through controlled cooling. It discusses the...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 December 2016
DOI: 10.31399/asm.tb.ascaam.t59190147
EISBN: 978-1-62708-296-9
... different phases, and reagents that reveal differentiation of the chemical composition of different phase constituents and chemical heterogeneity in a one-phase microregion. Very often the local tint of the precipitates appears due to the effect of the selective etching reagent, strictly attributed to...
Series: ASM Technical Books
Publisher: ASM International
Published: 31 December 2020
DOI: 10.31399/asm.tb.phtbp.t59310001
EISBN: 978-1-62708-326-3
.... Many solids are heterogeneous —that is, the atomic elements can arrange themselves into more than one type of structure under thermal equilibrium conditions. Different phases coexist in thermal equilibrium, and Gibbs defined the conditions for the number of coexisting phases ( P ) under thermal...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 November 2010
DOI: 10.31399/asm.tb.sap.t53000025
EISBN: 978-1-62708-313-3
... Abstract The microstructure of superalloys is highly complex, with a large number of dispersed intermetallics and other phases that modify alloy behavior through their composition, morphology, and distribution. This chapter provides an overview of the most notable phases, including the matrix...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 October 2011
DOI: 10.31399/asm.tb.mnm2.t53060013
EISBN: 978-1-62708-261-7
... structure of metals and their role in mechanical deformation, annealing, precipitation, and diffusion. It describes the concept of solid solutions and the effect of temperature on solubility and phase transformations. The chapter also discusses the formation of solidification structures, the use of...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 August 1999
DOI: 10.31399/asm.tb.lmcs.t66560005
EISBN: 978-1-62708-291-4
... Abstract This chapter discusses the development of the nomenclature used to describe the constitution and structure of metals and alloys, particularly the phases observed in the microstructure of steel. It also points out some of the problems with current nomenclature and provides...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 December 2016
DOI: 10.31399/asm.tb.ascaam.t59190vii
EISBN: 978-1-62708-296-9
... Abstract This chapter provides an overview of the microstructure-property relationships associated with aluminum-silicon alloys. It includes information on commercial designations and grades, phase compositions, solidification paths, alloying elements, and intermetallic phases. It also provides...
Series: ASM Technical Books
Publisher: ASM International
Published: 31 December 2020
DOI: 10.31399/asm.tb.phtbp.t59310029
EISBN: 978-1-62708-326-3
... more carbon (hypereutectoid steels) than the eutectoid composition. In these cases, cooling of the single-phase austenite first changes into a heterogeneous two-phase field before the eutectoid temperature is reached. In hypoeutectoid steels, a type of ferrite called proeutectoid ferrite forms before...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 August 2018
DOI: 10.31399/asm.tb.msisep.t59220193
EISBN: 978-1-62708-259-4
... the nucleation of a thermodynamically more stable phase. In the absence of nucleation, it is possible to keep systems away from the stable thermodynamic equilibrium. In a classical work, Turnbull ( Ref 5 ) was able, through the almost complete elimination of heterogeneities that could act as...
Book Chapter

Series: ASM Technical Books
Publisher: ASM International
Published: 01 August 2018
DOI: 10.31399/asm.tb.msisep.t59220001
EISBN: 978-1-62708-259-4
... Abstract This chapter discusses the engineering significance of steel and briefly describes its chemical composition, crystal structure, Fe-C phases, and associated characterization techniques. steel Humankind has used iron products since at least 1200 B.C. Even though iron is one of...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 March 2012
DOI: 10.31399/asm.tb.pdub.t53420117
EISBN: 978-1-62708-310-2
... peritectic reactions are almost never observed in practice. Fig. 6.1 Schematic of peritectic freezing Actually, the term peritectic , in the science of heterogeneous equilibria, has a broader meaning. The term may be used to define all reactions in which two or more phases (gas, liquid, solid...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 May 2018
DOI: 10.31399/asm.tb.hma.t59250047
EISBN: 978-1-62708-287-7
... Abstract This chapter covers the early studies and various discoveries by metals researchers to study the internal structure of metals. The topics covered include light microscopy, phase diagrams, X-ray diffraction, principles of precipitation hardening, and dislocation theory...
Series: ASM Technical Books
Publisher: ASM International
Published: 01 August 2018
DOI: 10.31399/asm.tb.msisep.t59220273
EISBN: 978-1-62708-259-4
... nitrocarburizing. It describes the primary objectives of each treatment along with processing sequences, process parameters, and related phase transformations. The chapter contains more than 100 images, including time-temperature diagrams, transformation curves, data plots, and detailed micro- and macrographs. It...