| About this Abstract |
| Meeting |
MS&T23: Materials Science & Technology
|
| Symposium
|
Grain Boundaries, Interfaces, and Surfaces: Fundamental Structure-Property-Performance Relationships
|
| Presentation Title |
A Potential Mechanism for Abnormal Grain Growth in Thin Films on c-sapphire |
| Author(s) |
Dominique Chatain, Blandine Courtois, Gerhard Dehm |
| On-Site Speaker (Planned) |
Dominique Chatain |
| Abstract Scope |
Abnormal grain growth (AAG) of (100) grains, in a (111) textured Ni film on (0001) sapphire, is observed upon annealing. The orientation transformation is driven by the anisotropy of biaxial elastic strain in the film induced by differential Ni/sapphire thermal expansion. AAG stops and (111) grain normal growth (NG) slows down when Ni is capped by an amorphous alumina layer. It is inferred that the mechanisms involved in AGG and NG are related to atom and vacancy diffusion along GBs from the Ni film free surface, which acts as a sink/source. GB motion mechanism in this single component is similar to that involved in diffusion induced grain boundary motion (DIGM).
The orientation relationships of the (111) and (100) grains on c-sapphire determine their misorientations. Thus, normal and abnormal rates of GB motion can be correlated to their misorientation. |