Variational methods in Material Science

seminar: New observations on the origins of hysteresis in phase transformations and metastability in the calculus of variations

speaker: Richard D. James (University of Minnesota, Minneapolis)

abstract: We present some recent measurements of hysteresis that resulted from a systematic program of tuning of the lattice parameters of some alloys by changing composition. The lattice parameters were tuned so that a certain nongeneric condition of compatibility was satisfied. It was observed that there is a sharp drop of the hysteresis of the transformation at the special lattice parameters. The data has some fascinating features, including an apparent singularity. Some exploratory calculations suggest that this is related to metastability phenomena in the calculus of variations, suggesting a sensitive dependence of local minimizers on certain conditions of compatibility. Joint work with Jerry Zhang and Stefan Mueller.

timetable:
Tue 10 Oct, 15:10 - 16:05, Aula Dini
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