|About this Abstract
||2017 TMS Annual Meeting & Exhibition
||Deformation and Transitions at Interfaces
||The Zero-energy Grain Boundary and Consequences to Grain Growth
||Ricardo H. R. Castro, Nazia Nafsin
|On-Site Speaker (Planned)
||Ricardo H. R. Castro
Nanocrystalline bulk materials (also called nanograined materials) are intrinsically unstable due to the excess energies coming from extensive grain boundary areas. Designed dopants prone to segregation to boundaries have been proposed to lower excess energies, increasing stability against coarsening and enabling the nanostructural features to survive high temperature processing and operational environments. It has been theoretically proposed that the grain boundary energy of a material can eventually zero as a function of dopant concentration, signifying negligible driving force for growth – an infinitely stable nanomaterial. In this work we use highly sensitive microcalorimetry to experimentally measure the absolute grain boundary energy of gadolinium doped nanocrystalline zirconia as a function of grain size and show that the energy can indeed reach a quasi-zero energy state (0.05 J.m-2) when a critical grain boundary dopant enrichment is achieved. This thermodynamic condition leads to unprecedented coarsening resistance.