Dynamics of ferroelastic domains in crystals and ceramics

Dynamic Mechanical Analysis

We know that minerals commonly show transformation twinning, e.g. CaTiO3 perovskite:

Twinning in CaTiO3 (Wang & Liebermann Phys Chem Miner 20 147-158 [1993])

How do domain walls respond to applied stress? What are the dynamics of domain movement approaching the phase transition temperature, Tc? Domain movement often lags the instantaneous elastic response of the lattice. It can show up as an anelastic effect:

.. which can be probed by carrying out a modulated stress experiment, and measuring the phase lag between the applied stress and the observed strain:

In our measurements we use three-point bend geometry. For small applied stress the strain response is dominated by the biasing of domains, with domain 1 or domain 2 growing in response to the stress, remembering that the top of the sample is in compression while the lower surface is in tension:

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