Interfaces and Pattern Formation in -transitions Hanu SEINER - - PowerPoint PPT Presentation

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Interfaces and Pattern Formation in -transitions Hanu SEINER - - PowerPoint PPT Presentation

Apr 30, 2023 105 likes •514 views

Interfaces and Pattern Formation in -transitions Hanu SEINER Institute of Thermomechanics, Czech Academy of Sciences, Prague (CZ) based on joint research with: Czech Technical University Charles University Faculty of Nuclear Sciences

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SLIDE 1

Interfaces and Pattern Formation in ω-transitions

Hanuš SEINER

Institute of Thermomechanics, Czech Academy of Sciences, Prague (CZ) based on joint research with:

Czech Technical University Faculty of Nuclear Sciences and Physical Engineering Charles University Faculty of Mathematics and Physics

HIA in SPT HIA in SPT Oxford, September 2016 Oxford, September 2016

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Interfaces and Pattern Formation in ω-transitions

Hanuš SEINER

Institute of Thermomechanics, Czech Academy of Sciences, Prague (CZ) based on joint research with:

Czech Technical University Faculty of Nuclear Sciences and Physical Engineering Charles University Faculty of Mathematics and Physics

(a commented literature search)

HIA in SPT HIA in SPT Oxford, September 2016 Oxford, September 2016

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SLIDE 3

Interfaces and Pattern Formation in ω-transitions

(commented literature search)

  • A. Devaraj et al. / Acta Materialia 60 (2012) 596–609
  • X. L. Wang et al. / Materials Characterization107 (2015) 149–155
  • H. Liu et al. / Acta Materialia 106 (2016) 162-170
  • F. Sun et al. / Acta Materialia 61 (2013) 6406–6417
  • E. Sukedai et al. / Materials Science and Engineering A350 (2003) 133 -138
  • B. Tang et al. / Computational Materials Science 53 (2012) 187–193
  • D. Wang et al. / PRL 105 (2010) 205702
  • X. Ren / Phys. Status Solidi B 251 (2014) 1982–1992

Talk outline:

  • 1. What are the ω-transitions and how they differ

from (thermoelastic) martensitic transitions

  • 2. Basic thermodynamics and principles
  • 3. Modelling: concepts and tools
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SLIDE 4
  • 1. What are the ω-transitions and how they differ

from (thermoelastic) martensitic transitions

THERMOELASTC MARTENSITES ω-TRANFORMING ALLOYS β-Ti ALLOYS

Cu-based, Ni-Ti-based, Fe-based Heusler (Mn-, Co-) Zr-based alloys Hf-based alloys Ti-Nb

Ti-V Ti-Mo Ti-Fe

Ti-Cr-Sn Ti-Mo-Zr-Al

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SLIDE 5
  • 1. What are the ω-transitions and how they differ

from (thermoelastic) martensitic transitions Martensitic transitions:

  • the high-symmetry phase (austenite) transforms

into the low-symmetry phase (martensite) upon cooling

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SLIDE 6
  • 1. What are the ω-transitions and how they differ

from (thermoelastic) martensitic transitions Martensitic transitions:

  • the high-symmetry phase (austenite) transforms

into the low-symmetry phase (martensite) upon cooling

  • r by mechanical

loading

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SLIDE 7
  • 1. What are the ω-transitions and how they differ

from (thermoelastic) martensitic transitions Martensitic transitions:

  • the high-symmetry phase (austenite) transforms

into the low-symmetry phase (martensite) upon cooling

  • the transition is reversible, diffusionless, athermal
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SLIDE 8
  • 1. What are the ω-transitions and how they differ

from (thermoelastic) martensitic transitions Martensitic transitions:

  • the high-symmetry phase (austenite) transforms

into the low-symmetry phase (martensite) upon cooling

  • the transition is reversible, diffusionless, athermal
  • typically formed

patterns are laminates

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SLIDE 9
  • 1. What are the ω-transitions and how they differ

from (thermoelastic) martensitic transitions Martensitic transitions:

  • the high-symmetry phase (austenite) transforms

into the low-symmetry phase (martensite) upon cooling

  • the transition is reversible, diffusionless, athermal
  • typically formed

patterns are laminates

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SLIDE 10
  • 1. What are the ω-transitions and how they differ

from (thermoelastic) martensitic transitions ω-transitions:

  • essentially a cubic-to-trigonal martensitic

transition + trigonal-to-hexagonal shuffle

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SLIDE 11
  • 1. What are the ω-transitions and how they differ

from (thermoelastic) martensitic transitions ω-transitions:

  • essentially a cubic-to-trigonal martensitic

transition + trigonal-to-hexagonal shuffle

β

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SLIDE 12
  • 1. What are the ω-transitions and how they differ

from (thermoelastic) martensitic transitions ω-transitions:

  • essentially a cubic-to-trigonal martensitic

transition + trigonal-to-hexagonal shuffle

β

ω

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SLIDE 13
  • 1. What are the ω-transitions and how they differ

from (thermoelastic) martensitic transitions ω-transitions:

  • omega phase can be obtained from beta

both by cooling and by heating

β

ω

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SLIDE 14
  • 1. What are the ω-transitions and how they differ

from (thermoelastic) martensitic transitions ω-transitions:

  • omega phase can be obtained from beta

both by cooling and by heating

β

ω

  • r by mechanical

loading

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SLIDE 15
  • 1. What are the ω-transitions and how they differ

from (thermoelastic) martensitic transitions ω-transitions:

  • the cooling route is reversible, athermal
  • the heating route is irreversible, isothermal

β

ω

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SLIDE 16
  • 1. What are the ω-transitions and how they differ

from (thermoelastic) martensitic transitions ω-transition patterns - cooling

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SLIDE 17
  • 1. What are the ω-transitions and how they differ

from (thermoelastic) martensitic transitions ω-transition patterns - cooling

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SLIDE 18
  • 1. What are the ω-transitions and how they differ

from (thermoelastic) martensitic transitions ω-transition patterns - heating

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SLIDE 19
  • 1. What are the ω-transitions and how they differ

from (thermoelastic) martensitic transitions ω-transition patterns - heating

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SLIDE 20
  • 1. What are the ω-transitions and how they differ

from (thermoelastic) martensitic transitions ω-transition patterns - loading

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SLIDE 21
  • 1. What are the ω-transitions and how they differ

from (thermoelastic) martensitic transitions ω-transition patterns - loading

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SLIDE 22
  • 2. Basic thermodynamics and principles

thermoelastic martensites ω-transforming materials

A M β ω

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SLIDE 23
  • 2. Basic thermodynamics and principles

thermoelastic martensites ω-transforming materials

A M β ω

Mo, V, Fe, ...

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SLIDE 24
  • 2. Basic thermodynamics and principles

what happens at low temperatures?

β ω

quenched heterogeneous distribution of β-stabilizers

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SLIDE 25
  • 2. Basic thermodynamics and principles

what happens at low temperatures?

β ω

quenched heterogeneous distribution of β-stabilizers at the low temperature, the diffusion is not activated

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SLIDE 26
  • 2. Basic thermodynamics and principles

what happens at high temperatures?

β ω

the of β-stabilizers are repelled from ω-nuclei by diffusion elastic and diffusional interactions make the ω-particles grow and coalesce

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SLIDE 27
  • 2. Basic thermodynamics and principles

what happens at high temperatures?

β ω

the of β-stabilizers are repelled from ω-nuclei by diffusion elastic and diffusional interactions make the ω-particles grow and coalesce

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SLIDE 28
  • 2. Basic thermodynamics and principles

what happens at high temperatures?

β ω

the of β-stabilizers are repelled from ω-nuclei by diffusion elastic and diffusional interactions make the ω-particles grow and coalesce

FUNNY KINETICS

shear modulus [GPa]

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SLIDE 29
  • 2. Basic thermodynamics and principles

what happens under stress?

β ω

the stress-induced ω-lamellas run across the concentration heterogeneities such laminate is chosen that it

  • ptimally relaxes the external forces
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SLIDE 30
  • 3. Modelling: concepts and tools

low temperature behavior – athermal ω – strain glass analogy

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SLIDE 31
  • 3. Modelling: concepts and tools

low temperature behavior – athermal ω – strain glass analogy

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SLIDE 32
  • 3. Modelling: concepts and tools

low temperature behavior – athermal ω – strain glass analogy

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SLIDE 33
  • 3. Modelling: concepts and tools

high temperature behavior – isothermal ω – precipitation

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SLIDE 34
  • 3. Modelling: concepts and tools

high temperature behavior – isothermal ω – precipitation the aspect ratio and preferred orientation of the particles can be controlled by external prestress, but the model does not predict lamination

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SLIDE 35
  • 3. Modelling: concepts and tools

stress-induced behavior – compatibility? stress-assisted compatibility ...the role of diffusion is unclear

the stress-induced ω-lamellas does not seem to be internally twinned however,

λ2 = 0.984

FelF − GelG = a⊗n σβ

ij nj = σω ij nj

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SLIDE 36
  • 3. Modelling: concepts and tools

stress-induced behavior – compatibility?

the concentration of β-stabilizers inside of the ω-lamellas is energetically very expensive. Under increased temperature, they should move out and stabilize the laminate.

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SLIDE 37
  • 3. Modelling: concepts and tools

stress-induced behavior – diffusive SME?

β β β β β β ω ω ω

stress heating under stress releasing stress & cooling

  • verheating
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SLIDE 38

Conclusions

  • there are no real conclusions – the understanding

at the continuum level is still an open question

  • understanding the interplay between the displacive

nature of the transition and the diffusion is essential for construction of reliable models

  • modelling so far: phase field simulations, not capturing

the lamination phenomena

  • take-home message: ω-related phenomena are rather

unexplored by the martensites/continuum community. More advertising needed!

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SLIDE 39

Conclusions

  • there are no real conclusions – the understanding

at the continuum level is still an open question

  • understanding the interplay between the displacive

nature of the transition and the diffusion is essential for construction of reliable models

  • modelling so far: phase field simulations, not capturing

the lamination phenomena

  • take-home message: ω-related phenomena are rather

unexplored by the martensites/continuum community. More advertising needed! THANK YOU FOR YOUR ATTENTION