Kolloquiumsvortrag (MAWI), Prof. Xian (Sherry) Chen, Hong Kong University of Science and Technology, / am 14.05.2018
14.05.2018 von 17:15 bis 18:00
Institute Ostufer, Geb. D, "Aquarium", Kaiserstr. 2, 24143 Kiel
Titel: Enhanced fatigue properties of phase-transforming materials by satisfying the cofactor conditions
Abstract:
Materials undergoing reversible solid-solid phase transformations provide emerging applications such as biomedical implants and stents, microelectronic actuators and sensors. The essential functionality of these materials is the ability to recover large deformation (i.e. 5~8%) before and after the structural transformation driven by temperature/stress/electromagnetic fields. The change of the lattice parameters and the breaking of symmetries, in turn, will cause the formation of microstructures, which lead to the accumulation of intrinsic defects at the stressed transition layer between phases. It has been theorized that the macroscopic behaviors strongly depend on the kinematic properties of the transition layer between phases. If the lattice parameters satisfy some special mathematical conditions (the cofactor conditions), we observe that the functional fatigue properties of the phase-transforming materials have been tremendously improved. In this talk, we will briefly review the mathematical framework of the cofactor conditions and introduce an algorithmic way to evaluate these conditions directly from the X-ray measurements. We will also show some experimental results how the functional fatigue properties are enhanced at various length scales.
Brief Biography of Prof. Xian(Sherry) Chen (HKUST)
Education:
Ph.D. and M.S., Aerospace Engineering and Mechanics, University of Minnesota, US
B.S., Materials Science and Engineering, Huazhong University of Science and Technology, China
Academic positions:
2015 – present, Assistant Professor, Mechanical and Aerospace Engineering, Hong Kong Univ. of Science and Technology, HK
2015 – 2016, Visiting Professor, Mechanical and Civil Engineering, California Institute of Technology, US
2014 – 2015, Postdoctoral Fellowship, Lawrence Berkeley National Lab, US
Research interests:
The research of our group integrates the theories of mechanics of crystalline solids with advanced structural characterization methods and algorithms to develop new phase-transforming materials. These materials have emerging applications in medical devices, microelectronics and energy conversion devices.
GRF grant (2016 – 2019): Investigation of microstructure-reversibility relationship for phase-transforming materials (Early Career Award)
GRF grant (2017 - 2020): Algorithmic approaches for high-throughput screen and discovery of new shape memory alloys
UGC grant (2017-2019): Measure 3D strain of phase transforming materials by Differential Interference Contrast optical system