Prof. Yanfei Gao
Department of Materials Science and Engineering
University of Tennessee, Knoxville

Integrated Studies of Computational Mechanics and Neutron Diffraction for Deformation and Failure Mechanisms in Advanced Structural Materials

ABSTRACT: The synergy of computational micromechanics, metallurgy, and neutron diffraction can lead to key insights in understanding the deformation and failure mechanisms in advanced alloys, as well as material processing techniques. Several illustrative examples will be presented in this talk. Primarily, we focus on the fatigue behavior, which has been mostly investigated by ex situ microstructural characterizations and crack growth monitoring with replica techniques. The in situ, nondestructive neutron diffraction technique, together with the multiscale simulations, will provide us a linkage between the stress analyses (top-down point of view) to the failure mechanisms on inter- and intra-granular scales (bottom-up point of view). An irreversible, hysteretic cohesive interface model is developed to simulate a steady fatigue crack, which generates a continuum deformation history as inputs for the micromechanical analysis of lattice strain evolution. Comparisons with our neutron diffraction tests suggest the intergranular damage near the crack tip process zone be the dominant mechanism for fatigue crack growth.

BIOGRAPHY: Dr. Gao is a Professor at Department of Materials Science and Engineering, University of Tennessee (UT), USA. He received his BS degree in Engineering Mechanics from Tsinghua University in 1999, and PhD from Princeton in 2003. He was a post-doctoral research associate at Brown University in 2003-2005. He has been a faculty member at UT since 2005, and he was a joint faculty at ORNL during 2005-2018. His research activities have been focusing on deformation and failure of advanced structural materials such as metallic glasses, superalloys, high entropy alloys, and structural ceramics. He has published more than 130 journal papers, many of which are in Journal of the Mechanics and Physics of Solids and Acta Materialia.