|About this Abstract
||2018 TMS Annual Meeting & Exhibition
||Thermal and Mechanical Stability of Nanocrystalline Materials
||Toward Understanding the Factors that Govern the Temperature Dependence of Mobility in FCC Metals
||Elizabeth Holm, Ian Chesser, Yutong Bi, Jonathan Humberson
|On-Site Speaker (Planned)
Computational and experimental surveys of grain boundaries in various FCC metals have shown that boundary structure as given by the macroscopic degrees of freedom determines the boundary enthalpy, with a scaling factor related to a scalar shear modulus. This is consistent with a broken bond model for boundary energy. However, the question remains whether this simple scaling applies to other boundary properties, such as mobility. In this study, we consider a class of sigma-3 grain boundaries that are known to vary in how their mobilities change with temperature. We find that the macroscopic degrees of freedom are insufficient to determine the thermal dependence of mobility. For the same boundary, mobility may increase with temperature in one material and decrease with temperature in another. We hypothesize that the mobility depends on the accessibility of particular boundary microstates governed by the generalized stacking fault energy.
||Planned: Supplemental Proceedings volume