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  • 1.  Electrically triggered martensitic transformation, what is that?

    Posted 05-04-2021 14:56
    Hello SMST Members,

    You may have read about shape memory ceramics, but have you heard that the martensite to austenite transformation in some ceramics can be driven directly with an electric field? Check it out in the latest issue of SMST Newswire (https://static.asminternational.org/amp/202103/56/).   


    Othmane

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    Othmane Benafan
    Materials Research Engineer
    NASA Glenn Research Center
    Cleveland OH
    (216) 433-8538
    ------------------------------
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  • 2.  RE: Electrically triggered martensitic transformation, what is that?

    Posted 05-18-2021 15:33
    Cool! There's so much new terminology floating around out there...I wonder how we can make sense of them all. 

    For example, are "paraelectroactive shape memory ceramics" the same thing as ferroelectric-ferroelastic ceramics, the only distinction being that it has (and can survive) a sizable shape change?  So why not call them "ferroelectric shape memory ceramics" (akin to how we refer to "ferromagnetic shape memory alloys")?

    In any case, it's neat to see how the mechanics behind SMAs translate into these other material classes! Excited to see more work like this in the future.

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    Ashley Bucsek
    Assistant Professor
    University of Michigan
    Ann Arbor MI
    7326758291
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    SMST 2024 Save the date


  • 3.  RE: Electrically triggered martensitic transformation, what is that?

    Posted 05-19-2021 09:09
    Thanks for your comment, Ashley.  Your are right that there are many terms out there and it can be confusing to keep them all separate.  However, in this case the new terms really are needed on the basis of new physics.  As you point out, the well-known "ferroelectrics" are also materials that can transform under an applied field. However, this article is talking about something that is thermodynamically different.  Paraelectric shape memory ceramics (like zirconia) are ^not^ ferroelectric, meaning that their crystal structures are more symmetric and they do not intrinsically carry any polarization that can interact with an electric field.  Their field-driven transformation is thus triggered by a different thermodynamic term (based on electrical susceptibility).  From a distance this may appear to be a subtle distinction, but it is quite different in its origins and practical effects.  So, we think there is indeed a need for new terminology for such materials. "Paraelectric shape memory materials" are in fact a new class in our field, and we are hoping to see more work on this concept in the future. Thanks for your interest in the article!
    Chris Schuh

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    Christopher Schuh
    Professor of Metallurgy
    MIT
    Cambridge MA
    617-452-2659
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  • 4.  RE: Electrically triggered martensitic transformation, what is that?

    Posted 05-19-2021 09:32
    Ah, very neat (and exciting)! Now I understand the "paraelectric" part, which is necessary to distinguish them from ferroelectrics. Thanks for the explanation.!

    ------------------------------
    Ashley Bucsek
    Assistant Professor
    University of Michigan
    Ann Arbor MI
    7326758291
    ------------------------------

    SMST 2024 Save the date