Dr. Yun-Yuan Chang [HPSTAR Postdoc]

Title: Influences of point defects on elasticity of candidate Earth's mantle minerals and superhard materials

Time: 16:00 - 17:00, August 29

Place: Auditorium Room 410, Building 6, HPSTAR (Shanghai)

Abstract:

Perfect crystals do not exist in nature. Defects in crystals modify their physical and chemical properties. Elastic properties relate stress to reversible strain and reflect the strength of interatomic bonding forces, which may be influenced by defects. In this talk, I will focus on defects associated with iron (Fe) and hydrogen (H) substitution in minerals, including wadsleyite, ringwoodite and phase D with application to interpreting the water content of the mantle from observed seismic wave speeds. In addition to mantle silicates, I will also discuss the influence of defects on the elastic properties of diamond and diamond related materials. Sound velocity measurements, high-pressure compression experiments, and Vickers hardness test were carried out on diamond and diamond related materials to investigate the potential relationship between hardness and elastic constants of superhard materials. Knowledge of elastic properties of diamond and other superhard materials will improve our ability to identify and design novel superhard materials in the future.

Biography of the Speaker:

Dr. Yun-Yuan Chang obtained her Ph.D. at the Department of Earth and Planetary Sciences in Northwestern University with Prof. Steven Jacobsen and Prof. Craig Bina. Her research focuses on mineral physics and material sciences. Dr. Chang is currently working with Prof. Jung-Fu Lin as a postdoc at HPSTAR.