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homogenous nucleation

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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
... nucleating system as a homogeneous phase using the classical nucleation theory, along with heterophase fluctuations that led to the formation of precipitates. It discusses the gas cluster dynamics using the kinetic approach to describe nucleation. The article presents key parameters, such as cluster...
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
... specify how to compute Δ F * in Eq 25 , the activation energy of nucleation. This gives the flexibility to choose any nucleation theory for the model. In the classical nucleation theory for homogeneous nucleation, for example: (Eq 27) Δ F * = α σ d / ( Δ f V ) d − 1...
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
... t 50 and d decrease with the prior strain. It should be noted that the expressions discussed in these two sections are valid for the ideal case of continuous, homogeneous nucleation and isotropic, three-dimensional growth. Equivalent relations can be readily derived for the other dimensional...
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
... 7 Fig. 6 Influence of undercooling on eutectic cell count in flake graphite cast iron. Source: Ref 8 Homogeneous nucleation is improbable in cast iron because typical undercoolings are much smaller than required by the theory of homogeneous nucleation (1 to 10 °C, or 2 to 20 °F...
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
... vector, b. Source: Ref 38 Stronger departures from classical behavior can be expected in the limit of homogeneous martensitic nucleation, which requires high driving forces approaching the critical driving force for lattice instability. The data points in Fig. 7 represent the measured critical...
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
... metals cannot occur as a result of any classical nucleation processes, such as those involving the rearrangement of atoms (alternatively stated, the condensation of vacancies) to create an embryonic bubble. The impossibility of homogeneous nucleation is, of course, widely accepted. What may be less...
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
... Outgassing and outdiffusion —affects nucleation and film contamination Homogeneity of the surface —affects uniformity of film properties over the surface In particular, the surface morphology can have an important effect on the film properties. Figure 1 shows the effect of surface morphology and...
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...
Series: ASM Handbook
Volume: 14A
Publisher: ASM International
Published: 01 January 2005
DOI: 10.31399/asm.hb.v14a.a0004019
EISBN: 978-1-62708-185-6
... materials, particles may affect the homogeneity and magnitude of dislocation substructure that evolves. In low-SFE materials, particles may affect the evolution of substructure, serve as nucleation sites for dynamic recrystallization, as well as serve as obstacles to boundary migration during the...
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
... melt supersaturation to meet the requirement for spontaneous nucleation. This barrier to the generation of nuclei from a homogeneous melt, imposed by thermodynamics, makes it unlikely that appreciable nucleation occurs by this mechanism. Instead, nucleation is initiated on particles purposely...
Series: ASM Handbook
Volume: 22A
Publisher: ASM International
Published: 01 December 2009
DOI: 10.31399/asm.hb.v22a.a0005421
EISBN: 978-1-62708-196-2
... simultaneously occurring stages, that is, nucleation, growth, and coalescence. An important requirement for cavitation during deformation under either conventional hot working (high-strain-rate) conditions or superplastic forming is the presence of a tensile stress. Under conditions of homogeneous compression...
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...
Series: ASM Handbook
Volume: 22A
Publisher: ASM International
Published: 01 December 2009
DOI: 10.31399/asm.hb.v22a.a0005434
EISBN: 978-1-62708-196-2
... been used for growing materials, for example, single-crystal or polycrystalline wafers, fibers, porous materials, particles, and so on. Sometimes, solid particles can even be grown in the gas phase without solid substrates (homogeneous nucleation). Growth is usually performed under vacuum conditions...
Series: ASM Desk Editions
Publisher: ASM International
Published: 01 December 1998
DOI: 10.31399/asm.hb.mhde2.a0003204
EISBN: 978-1-62708-199-3
... Abstract This article discusses different heat treating techniques, including quenching, homogenizing, annealing, stress relieving, stress equalizing, quench hardening, strain hardening, tempering, solution heat treating, and precipitation heat treating (age hardening) for different grades of...
Series: ASM Handbook
Volume: 4E
Publisher: ASM International
Published: 01 June 2016
DOI: 10.31399/asm.hb.v04e.a0006261
EISBN: 978-1-62708-169-6
... Abstract This article provides information on nickel alloying elements, and the heat treatment processes of various nickel alloys for applications requiring corrosion resistance and/or high-temperature strength. These processes are homogenization, annealing, solution annealing, solution...
Series: ASM Handbook
Volume: 4B
Publisher: ASM International
Published: 30 September 2014
DOI: 10.31399/asm.hb.v04b.a0005940
EISBN: 978-1-62708-166-5
.... Distortion engineering aims to compensate distortion using the so-called compensation potential (Level 3). Level 3 discusses the measures to improve homogeneity, and respectively the symmetry, of the carriers of the distortion potential. The article also discusses the compensation of the resulting size and...
Series: ASM Handbook
Volume: 4E
Publisher: ASM International
Published: 01 June 2016
DOI: 10.31399/asm.hb.v04e.a0006266
EISBN: 978-1-62708-169-6
... Abstract Cast nickel-base alloys are used extensively in corrosive-media and high-temperature applications. This article briefly reviews the common types of heat treatments of nickel alloy castings: homogenization, stress relieving, in-process annealing, full annealing, solution annealing...
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
... (grain boundaries) with adjacent crystals. This process of forming nuclei in the freezing melt and their subsequent growth is characterized as a nucleation and growth process. Fig. 13 Nucleation and growth during solidification. Source: Ref 2 Nucleation can occur by either homogeneous or...