MSE Seminar: Fan Yang, Precipitate Phases in Several High Temperature Shape Memory Alloys

PhD Candidate advised by Dr. Michael Mills, Department of Materials Science and Engineering, The Ohio State University

Abstract

Initiated by the aerospace industry, there has been a great interest to develop high temperature shape memory alloys (HTSMAs) for actuator type of application at elevated temperatures. Several NiTi based ternary systems have been shown to be potential candidates for HTSMAs and this work focuses on one or more alloys in the TiNiPt, TiNiPd, NiTiHf, NiPdTiHf systems, with a focus on materials characterization that aims to investigate microstructural evolution of the alloys as a function of heat treatment. The information gained through the study can serve as guidance for future alloy processing. The emphasis of this work is to describe novel precipitate phases that are formed under aging in the ternary systems and one quaternary system. Employing conventional transmission electron microscopy (TEM), high resolution high angle annular dark field (HAADF) scanning transmission electron microscopy (STEM), 3D atom probe tomography (3D APT), as well as ab initio calculations, the complete description of the unit cell for the new precipitates was determined.

Bio

Fan Yang obtained his B.S. from the School of Materials and Metallurgy at Northeastern University (PRC) in 2005. After graduation from college, he came to the MSE department at the Ohio State University for graduate school. He started working on phase field simulations of microstructural evolution of on a titanium alloy from 2005 and obtained his M.S. in 2008. He switched to work on High Temperature Shape Memory Alloys (HTSMA) for his Ph.D. work, by employing various characterization methods in electron microscopy. His favorite pastime involves movies, music, hiking, and traveling.