College of Engineering Seminars & Speakers

College of Engineering Seminars & Speakers

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Event Detail Information

Event Detail Information

Speaker Michael Mills, Ohio State University
Date Mar 26, 2012
Time 4:00 pm  
Location Room 100 Materials Science and Engineering Building
Sponsor Department of Materials Science and Engineering
Event type seminar
Views 3107
Originating Calendar MatSE Seminars
"Characterization of novel precipitate phases in high temperature shape memory alloys and understanding their effect on shape memory properties" - The effects of aging on mechanical and shape memory properties of high-temperature shape memory alloys Ni-49.7Ti-20Pt (at.%) and Ni-29.7Ti-20Hf were investigated in order to understand aging effects on transformation strain, work output and dimensional stability under cyclic load biased tests. Aging results in precipitation of a previously unidentified phases. The precipitate phases have been analyzed with electron diffraction, high-resolution STEM HAADF imaging and atom probe tomography. The precipitates are closely related to the high temperature cubic B2 phase, but have novel crystal structures. The mechanisms by which these precipitates improve shape memory response is being explored through detailed characterization of martensite and dislocation interaction with precipitates, coupled with phase field and finite element modeling. The present state of understanding of the microstructure-property relationships in these high temperature shape memory alloys will be discussed.