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avrami model

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Series: ASM Handbook
Volume: 22A
Publisher: ASM International
Published: 01 December 2009
DOI: 10.31399/asm.hb.v22a.a0005459
EISBN: 978-1-62708-196-2
... methodologies. These include JMAK (Avrami) models, topological models, and mesoscale physics-based models. microstructure evolution thermomechanical processing nickel-base superalloys avrami model topological model mesoscale physics-based model THE MODELING OF MICROSTRUCTURE EVOLUTION during...
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: 4E
Publisher: ASM International
Published: 01 June 2016
DOI: 10.31399/asm.hb.v04e.a0006272
EISBN: 978-1-62708-169-6
... precipitates ( Ref 36 ). This is shown in Table 3 ( Ref 36 ). Staley ( Ref 20 ) agreed that n can vary with the nucleation rate and morphology of the precipitate; however, no changes were made to the basic quench factor analysis model. Values of <italic>n</italic> in the Avrami kinetic law Table 3...
Series: ASM Handbook
Volume: 14A
Publisher: ASM International
Published: 01 January 2005
DOI: 10.31399/asm.hb.v14a.a0009002
EISBN: 978-1-62708-185-6
... working and key processes that control microstructure evolution: dynamic recovery, static recovery, recrystallization, and grain growth. Some of the key phenomenological descriptions of plastic flow and microstructure evolution are also summarized. The article concludes with a discussion on the modeling...
Series: ASM Handbook
Volume: 4B
Publisher: ASM International
Published: 30 September 2014
DOI: 10.31399/asm.hb.v04b.a0005934
EISBN: 978-1-62708-166-5
.... The analog signal from the thermocouple is converted to a digital value using an analog-to-digital converter card and a personal computer. The cooling curve digital time-temperature data are saved for subsequent computational work. Quench Factor Correlations The quench factor is based on the Avrami...
Series: ASM Handbook
Volume: 22A
Publisher: ASM International
Published: 01 December 2009
DOI: 10.31399/asm.hb.v22a.a0005401
EISBN: 978-1-62708-196-2
... Abstract The modeling and simulation of texture evolution for titanium alloys is often tightly coupled to microstructure evolution. This article focuses on a number of problems for titanium alloys in which such coupling is critical in the development of quantitative models. It discusses...
Series: ASM Handbook
Volume: 22A
Publisher: ASM International
Published: 01 December 2009
DOI: 10.31399/asm.hb.v22a.a0005425
EISBN: 978-1-62708-196-2
... of: Deformation and strain hardening, such as Schmid's law and the Hollomon equation Kinetics of recrystallization (such as the Avrami equation), grain growth (such as the Beck equation), and precipitation/phase transformation Ductility for solid-state processes Similarly, phenomenological models...
Series: ASM Handbook
Volume: 1A
Publisher: ASM International
Published: 31 August 2017
DOI: 10.31399/asm.hb.v01a.a0006314
EISBN: 978-1-62708-179-5
... Expressions similar to Eq 30 have also been proposed by Johnson and Mehl ( Ref 3 ) and Avrami ( Ref 55 ); therefore; the modification brought to Eq 28 is known in the literature as the Kolmogorov-Johnson-Mehl-Avrami model. In the general case, it is recommended to perform numerical integration...
Series: ASM Handbook
Volume: 22A
Publisher: ASM International
Published: 01 December 2009
DOI: 10.31399/asm.hb.v22a.a0005409
EISBN: 978-1-62708-196-2
... Abstract This article focuses on the modeling of microstructure evolution during thermomechanical processing in the two-phase field for alpha/beta and beta titanium alloys. It also discusses the mechanisms of spheroidization, the coarsening, particle growth, and phase decomposition in titanium...
Series: ASM Handbook
Volume: 22A
Publisher: ASM International
Published: 01 December 2009
DOI: 10.31399/asm.hb.v22a.a0005414
EISBN: 978-1-62708-196-2
... models for recrystallization kinetics have been developed based on the well-known Johnson-Mehl-Avrami-Kolmogorov (JMAK) equation: (Eq 6) X = 1 − exp ⁡ ( − 0.693 ( t t 0.5 ) n ) where X is the fraction recrystallized at time t , t 0.5 is the time for 50...
Series: ASM Handbook
Volume: 14A
Publisher: ASM International
Published: 01 January 2005
DOI: 10.31399/asm.hb.v14a.a0003989
EISBN: 978-1-62708-185-6
...-dynamically recrystallized grain size may be reduced by increasing the total strain or strain rate. Increasing the temperature or hold time tends to increase the meta-dynamic or statically recrystallized grain size. The following is a description of a model of classical Mehl-Johnson-Avrami basis...
Series: ASM Handbook
Volume: 22A
Publisher: ASM International
Published: 01 December 2009
DOI: 10.31399/asm.hb.v22a.a0005432
EISBN: 978-1-62708-196-2
..., distributing nuclei of recrystallized grains, growing the recrystallized grains, and updating the dislocation density. The article concludes with information on the developments in CA simulations. cellular automaton model static recrystallization dynamic recrystallization microstructure dislocation...
Series: ASM Handbook
Volume: 1A
Publisher: ASM International
Published: 31 August 2017
DOI: 10.31399/asm.hb.v01a.a0006307
EISBN: 978-1-62708-179-5
... without going into dislocation theory. The article discusses modeling of hardness in cast iron based on a regular solution equation in which the properties of each phase depend on chemical composition and coarseness. It describes the evaluation of material parameters from the tensile stress-strain curve...
Series: ASM Handbook
Volume: 22B
Publisher: ASM International
Published: 01 November 2010
DOI: 10.31399/asm.hb.v22b.a0005517
EISBN: 978-1-62708-197-9
... Abstract This article presents the background to the CALculation of PHAse Diagrams (CALPHAD) method, explaining how it works, and how it can be applied in industrial practice. The extension of CALPHAD methods as a core basis for the modeling of generalized material properties is explored...
Series: ASM Handbook
Volume: 6A
Publisher: ASM International
Published: 31 October 2011
DOI: 10.31399/asm.hb.v06a.a0005604
EISBN: 978-1-62708-174-0
... of the simulation results, simplifications and assumptions as a prerequisite for modeling, and thermomechanical simulation. The article concludes with information on the sensitivity of the material properties data with respect to the simulation results. It also provides hints on the central challenge of having...
Series: ASM Handbook
Volume: 14A
Publisher: ASM International
Published: 01 January 2005
DOI: 10.31399/asm.hb.v14a.a0003971
EISBN: 978-1-62708-185-6
... volume fraction typically follows a sigmoidal (“Avrami”) dependence on strain or time. Phenomenological models of dynamic and static recrystallization have been developed for a variety of steels, aluminum alloys, and nickel-base alloys. Grain growth during heat treatment of single-phase alloys without...
Series: ASM Handbook
Volume: 22A
Publisher: ASM International
Published: 01 December 2009
DOI: 10.31399/asm.hb.v22a.a0005408
EISBN: 978-1-62708-196-2
... that U RV = 200 kJ/mol. The recrystallization model is an extension of the classical Johnson-Mehl-Avrami-Kolmogorov approach, treating recrystallization as a nucleation and growth process: (Eq 7) X ˙ = ( 1 − X ( t ) ) ⋅ N ( t ) ⋅ 4 π ⋅ r ( t ) 2 ⋅ G ( t...
Series: ASM Handbook
Volume: 6A
Publisher: ASM International
Published: 31 October 2011
DOI: 10.31399/asm.hb.v06a.a0005599
EISBN: 978-1-62708-174-0
... Abstract This article focuses on the general internal state variable method, and its simplification, for single-parameter models, in which the microstructure evolution may be treated as an isokinetic reaction. It explains that isokinetic microstructure models are applied to diffusional...
Series: ASM Handbook
Volume: 4C
Publisher: ASM International
Published: 09 June 2014
DOI: 10.31399/asm.hb.v04c.a0005882
EISBN: 978-1-62708-167-2
... Abstract This article provides a discussion on the analytical modeling and simulation of residual stress states developed in steel parts and the reasons for these varied final stress states. It illustrates how the metallurgical phase transformation of steel alloys can be applied...
Series: ASM Handbook
Volume: 22B
Publisher: ASM International
Published: 01 November 2010
DOI: 10.31399/asm.hb.v22b.a0005524
EISBN: 978-1-62708-197-9
... were rationalized based on transmission electron microscopy, synchrotron radiation, and computational thermodynamic calculations. Kelly ( Ref 45 ) used CT and CK tools to obtain the parameters for the Johnson-Mehl-Avrami-Kologoromov model, which is then coupled with a thermal model for laser near...