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heterogeneous nucleation

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Series: ASM Handbook
Volume: 4E
Publisher: ASM International
Published: 01 June 2016
DOI: 10.31399/asm.hb.v04e.a0006250
EISBN: 978-1-62708-169-6
.... annealing castings deformation diffusion coefficient grain growth heat treatment heterogeneous nucleation homogeneous nucleation homogenization isothermal transformation nonferrous metals precipitation hardening recrystallization recrystallization temperature solid-state phase transformation...
Book: Casting
Series: ASM Handbook
Volume: 15
Publisher: ASM International
Published: 01 December 2008
DOI: 10.31399/asm.hb.v15.a0005207
EISBN: 978-1-62708-187-0
.... Nucleation during solidification is a thermally activated process involving a fluctuational growth in the sizes of clusters of solids. The article describes nucleation phenomenon such as homogeneous nucleation and heterogeneous nucleation. It discusses various grain refinement models, such as carbide-boride...
Series: ASM Handbook
Volume: 22A
Publisher: ASM International
Published: 01 December 2009
DOI: 10.31399/asm.hb.v22a.a0005410
EISBN: 978-1-62708-196-2
... inhomogeneities. These inhomogeneities can be, for instance, a solute segregation in the vicinity of a defect such as a dislocation. Phase-field simulations therefore allow the description of heterogeneous nucleation associated with a variation of the driving force. Moreover, in the case of solid-solid phase...
Series: ASM Handbook
Volume: 22A
Publisher: ASM International
Published: 01 December 2009
DOI: 10.31399/asm.hb.v22a.a0005415
EISBN: 978-1-62708-196-2
... dimensions ( d = 2). Note that both σ and Δ f V are position dependent and can incorporate location-dependent interaction energy terms that constitute defect-assisted (heterogeneous) nucleation. When a nucleating phase differs sufficiently in crystal lattice from the matrix phase, coherency...
Series: ASM Handbook
Volume: 22A
Publisher: ASM International
Published: 01 December 2009
DOI: 10.31399/asm.hb.v22a.a0005403
EISBN: 978-1-62708-196-2
... dynamic recrystallization (DDRX). The article discusses the assumptions and simplifications for the Avrami analysis. It describes the effects of nucleation and growth rates on recrystallization kinetics and recrystallized grain size based on the Johnson-Mehl-Avrami-Kolmogorov model for static...
Series: ASM Handbook
Volume: 11
Publisher: ASM International
Published: 15 January 2021
DOI: 10.31399/asm.hb.v11.a0006775
EISBN: 978-1-62708-295-2
... Abstract This article focuses on characterizing the fracture-surface appearance at the microscale and contains some discussion on both crack nucleation and propagation mechanisms that cause the fracture appearance. It begins with a discussion on microscale models and mechanisms for deformation...
Book: Casting
Series: ASM Handbook
Volume: 15
Publisher: ASM International
Published: 01 December 2008
DOI: 10.31399/asm.hb.v15.a0005213
EISBN: 978-1-62708-187-0
... sodium, potassium, calcium, strontium, barium, yttrium, and the lanthanides, act as inoculants in FG iron and can therefore be considered to play a significant role in the heterogeneous nucleation of the austenite-FG eutectic ( Ref 9 , Ref 11 , Ref 12 , Ref 13 ). High silicon concentrations in the...
Series: ASM Handbook
Volume: 22A
Publisher: ASM International
Published: 01 December 2009
DOI: 10.31399/asm.hb.v22a.a0005435
EISBN: 978-1-62708-196-2
..., while blocks at the right denote a sequence of dynamic phenomena interacting with these structural levels. As denoted by the interconnections, initial nucleation is sensitive to interfacial defects generated by the processing history, determining the initial number density, N i , of heterogeneous...
Book: Casting
Series: ASM Handbook
Volume: 15
Publisher: ASM International
Published: 01 December 2008
DOI: 10.31399/asm.hb.v15.a0005220
EISBN: 978-1-62708-187-0
... evident is that classical heterogeneous nucleation, although clearly significantly easier, is still not sufficiently easy to make pore nucleation possible in cast products ( Ref 1 ). Thus, nucleation of porosity by any conceivable process is almost certainly impossible. In other words, interfaces in...
Series: ASM Handbook
Volume: 5
Publisher: ASM International
Published: 01 January 1994
DOI: 10.31399/asm.hb.v05.a0001286
EISBN: 978-1-62708-170-2
.... When atoms condense they form nuclei. If the surface is of the same material as the depositing atoms, the process is called homogeneous nucleation ; if they are of different materials, the process is call heterogeneous nucleation . In semiconductor terminology, heterogeneous nucleation forms...
Series: ASM Handbook
Volume: 22A
Publisher: ASM International
Published: 01 December 2009
DOI: 10.31399/asm.hb.v22a.a0005405
EISBN: 978-1-62708-196-2
... monitoring via an inspection scheme. This article begins with a discussion on the stages of the fatigue damage process. It describes hierarchical multistage fatigue modeling and several key points regarding the physics of crack nucleation and microstructurally small crack propagation in the HCF regime. The...
Book: Casting
Series: ASM Handbook
Volume: 15
Publisher: ASM International
Published: 01 December 2008
DOI: 10.31399/asm.hb.v15.a0005236
EISBN: 978-1-62708-187-0
... the development of the mushy zone upon solidification. It is assumed that nucleation of grains takes place on heterogeneous particles present in the melt as soon as a critical undercooling is reached. Because such nucleation behavior is only dependent on undercooling, it is considered as an...
Book: Casting
Series: ASM Handbook
Volume: 15
Publisher: ASM International
Published: 01 December 2008
DOI: 10.31399/asm.hb.v15.a0005189
EISBN: 978-1-62708-187-0
... interrelationship between phase diagrams and thermodynamics is presented. The article discusses processes that generally limit the rates of chemical processes. These include nucleation of the product phase and interphase mass transport. The article provides a discussion on the dissolution of alloy with melting...
Series: ASM Handbook
Volume: 3
Publisher: ASM International
Published: 27 April 2016
DOI: 10.31399/asm.hb.v03.a0006222
EISBN: 978-1-62708-163-4
... heterogeneous nucleation. Homogenous nucleation occurs when nucleation takes place throughout the bulk of the liquid without preference for any point; that is, the probability of nucleation is the same everywhere within the volume of the liquid. When a solid nucleates preferentially at certain points in the...
Book: Casting
Series: ASM Handbook
Volume: 15
Publisher: ASM International
Published: 01 December 2008
DOI: 10.31399/asm.hb.v15.a0005211
EISBN: 978-1-62708-187-0
... heterogeneous nucleation, and the second solid nucleates contiguously and heterogeneously but may not necessarily nucleate on the first solid phase. In Fig. 5 , regions marked 1 and 2 are termed normal or regular eutectic structures and constitute structures formed with two solids growing without crystalline...
Book: Casting
Series: ASM Handbook
Volume: 15
Publisher: ASM International
Published: 01 December 2008
DOI: 10.31399/asm.hb.v15.a0005222
EISBN: 978-1-62708-187-0
... means that homogeneous nucleation of pores is extremely difficult and is unlikely to occur in practice. In castings, nucleation of pores can be expected to occur primarily at heterogeneous nucleation sites. The classical theory of homogeneous nucleation is extended to heterogeneous nucleation. The...
Series: ASM Handbook
Volume: 22A
Publisher: ASM International
Published: 01 December 2009
DOI: 10.31399/asm.hb.v22a.a0005438
EISBN: 978-1-62708-196-2
... users to discern the best models and for modelers to further refine their efforts. The mechanistic nature of a martensite kinetics model demands a multilevel modeling hierarchy, as shown in Fig. 2 . This hierarchy establishes the fundamental mechanisms involved in the heterogeneous nucleation of...
Series: ASM Handbook
Volume: 4E
Publisher: ASM International
Published: 01 June 2016
DOI: 10.31399/asm.hb.v04e.a0006287
EISBN: 978-1-62708-169-6
... treatment, so that the particles act as heterogeneous nucleation sites for the η phase. Precipitates are fine phases or clusters that form during aging of a supersaturated solid solution (see also the article “Age Hardening of Aluminum Alloys” in this Volume). In many (but not all) metals, alloying...
Book: Casting
Series: ASM Handbook
Volume: 15
Publisher: ASM International
Published: 01 December 2008
DOI: 10.31399/asm.hb.v15.a0005214
EISBN: 978-1-62708-187-0
..., heterogeneous nucleation of β occurs at the α/liquid interface at the peritectic equilibrium temperature, T p . If nucleation is limited to a few locations, and lateral growth of the β-nuclei does not readily occur, no continuous layer of the peritectic phase is formed. Two types of the peritectic reactions...
Series: ASM Handbook
Volume: 4E
Publisher: ASM International
Published: 01 June 2016
DOI: 10.31399/asm.hb.v04e.a0006268
EISBN: 978-1-62708-169-6
... lattice sites or dissolution of an old and heterogeneous nucleation of a new precipitate. The strain fields around the precipitates—and the critical shear stress required to cut them—increase with their size, and mechanical strength further increases. If the crystallographic parameters of the emerging...