Mobility of martensitic interfaces

Grujičić, M.; Olson, Gregory B.; Owen, W. S.

doi:10.1007/bf02670359

Cited by 89 publications

(64 citation statements)

References 12 publications

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“…The parameters pˆ0:5 and bˆ1:5 in equation (A 13) are predicted theoretically (Kocks et al 1975, Grujicic et al 1985 for the interaction of interfacial dislocations with the strain ®eld of solute atoms. These parameters allowed the best ®t of experimental data for normalized activation energy versus normalized driving force for a number of steels (Ghosh and Olson 1994).…”

Section: …7 †mentioning

confidence: 93%

“…must be prescribed. The theoretical form of the martensitic interface mobility has to be derived through an extension of thermally activated deformation theory, and experimentally veri®ed in single-interfac e experiments in thermoelastic systems (Grujicic, Olson and Owen 1985). Mobility parameters for non-thermoelasti c ferrous alloys have been determined by interpreting isothermal nucleation kinetics in terms of interface-controlled barrierless heterogeneous nucleation (Olson and Cohen 1986).…”

Section: …7 †mentioning

confidence: 99%

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Numerical modelling of martensitic growth in an elastoplastic material

Levitas

Idesman

Olson

et al. 2002

Philosophical Magazine A

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A ®nite-strain-continuum thermomechanical approach is applied to the problem of temperature-induced martensitic transformation in elastoplastic materials. The key issue is to determine the transformation-induced stress and plastic strain ®elds and their eOE ect on the thermodynamics and kinetics of transformation. The problems of appearance and growth of a temperatureinduced rectangular martensitic unit in an austenitic matrix in both bulk and near-free-surface environments are formulated, solved and analysed. Very complex and heterogeneous stress±strain ®elds in the austenite and martensite phases and their non-monotonic time variation are predicted. Plastic shear strain at some points can reach 60% and, after an elastic growth stage, change sign and vary by 40%. The interface velocity as a function of temperature and interface position is calculated. After the appearance of a martensitic particle, transformation work, which is the only variable part of the interface driving force, decreases by a factor of two during lengthening of the particle by 10%. The component of the athermal interfacial friction due to dislocation forest hardening increases signi®cantly as well, leading to interface deceleration and growth arrest. A free surface does not signi®cantly aOE ect the driving force until its distance from the moving interface falls below 0.75 times the particle thickness. Then the transformation work increases while the accumulated plastic strain and associated dislocation forest hardening decrease sharply. If the interface is not arrested at this point, it then accelerates to the free surface where an asymmetric plastic zone leaves`tent-shaped' surface relief. The motion of a small step at the martensitic plate interface is studied as well. In contrast with elastic growth, the thermodynamic conditions for lengthening and thickening are almost equivalent for plastic growth. The results obtained allowed us to address the following fundamental problems: ®rstly, the morphological transition from plate to lath martensite; secondly, the relation of thermally activated kinetics at the interface level to athermal kinetics at the macrolevel; thirdly, the concentration of

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Section: …7 †mentioning

confidence: 93%

Section: …7 †mentioning

confidence: 99%

Numerical modelling of martensitic growth in an elastoplastic material

Levitas

Idesman

Olson

et al. 2002

Philosophical Magazine A

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“…Comparing, α X ≈ 1 should reflect a less intense feedback from the relaxation of the transformation strains. We propose that α X ≈ 1 stems from stress-accommodating micro-domains within the martensite unit 14,39,42 as well as from slip during the motion of the martensite-austenite interface [43][44][45] .…”

Section: The Autocatalytic Pathmentioning

confidence: 99%

Autocatalysis, Entropic Aspects and the Martensite Transformation Curve in Iron-Base Alloys

Guimarães

Rios

2017

Mat. Res.

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This study advances a methodology that consolidates the description of time-dependent (isothermal) as well as time-independent (athermal) martensitic transformation curves. Our model is applied in an extended 3-space, thus permitting inclusion of the effects of autocatalysis on nucleation to be distinguished from the initiation of the transformation, as influenced by entropic barriers. Autocatalysis is then considered as a mechanism for circumventing the effect of the latter. The utility of this proposed mathematical formalism was validated with a database consisting of seven different steels that transform athermally or isothermally.

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“…Minimizing interphase misfit is important for maximizing driving force for precipitation to increase finescale particle number density. Additionally, large coherency strains can be an obstacle for martensite interface motion during phase transformation, increasing interfacial frictional work and transformation hysteresis [10], which is detrimental to actuator applications with narrow temperature ranges. Lastly, early coherency loss during particle growth and coarsening would prohibit dislocation cutting and cause premature bypass, leading to non-optimal peak strength values [11].…”

Section: Design Objectivesmentioning

confidence: 99%

Design of Heusler Precipitation Strengthened NiTi- and PdTi-Base SMAs for Cyclic Performance

Frankel

Olson

2015

Shap. Mem. Superelasticity

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For a wide range of actuation applications, the performance of NiTi-based shape memory alloys is limited by cyclic instability associated with accommodation slip. For medical applications, low-Ni compositions are also desirable. Increasing yield strength via precipitation of a coherent nanoscale Ni 2 TiAl-type Heusler phase from a supersaturated B2 matrix is an effective approach for eliminating slip in order to improve the stability of the functional response and increase the structural fatigue life. Quaternary additions that partition into the L2 1 Heusler phase, such as Zr or Pd, are favorable for reducing interphase misfit and maintaining coherency during aging. Phase relations and precipitation kinetics in quaternary Ni(TiZrAl), low-Ni (PdNi)(TiAl), and Ni-free (PdFe)(TiAl) systems are summarized from TEM and atom probe tomography data in the literature. Strengthening behavior during isothermal aging is compared in the NiTiZrAl and PdNiTiAl systems, and recent work characterizing a high-strength, low-Ni ''Hybrid'' (PdNi)(TiZrAl) alloy is presented. A systems design approach is taken in which an optimal microstructure for peak strengthening is identified while other property objectives such as transformation temperature, misfit, radiopacity, and biocompatibility are satisfied.

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Mobility of martensitic interfaces

Cited by 89 publications

References 12 publications

Numerical modelling of martensitic growth in an elastoplastic material

Numerical modelling of martensitic growth in an elastoplastic material

Autocatalysis, Entropic Aspects and the Martensite Transformation Curve in Iron-Base Alloys

Design of Heusler Precipitation Strengthened NiTi- and PdTi-Base SMAs for Cyclic Performance

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