|About this Abstract
||2018 TMS Annual Meeting & Exhibition
||Thermal and Mechanical Stability of Nanocrystalline Materials
||Thermal Stability of Thin Ni-Fe Films on Sapphire
||Amit Sharma, Aakash Kumar, David J. Srolovitz, Eugen Rabkin
|On-Site Speaker (Planned)
We deposited thin Ni-Fe bilayers on c-plane sapphire substrates at room temperature. Annealing the films at elevated temperatures led to full intermixing of the layers. The Ni-rich films exhibited a strong fiber  texture, and their prolonged annealing at high temperature resulted in full dewetting and formation of -oriented single crystalline particles. The dewetting of the Fe-richer films proceeded differently. At the temperature of 450 °C we observed the onset of abnormal grain growth in the films: sparsely spaced -oriented grains nucleated in the -textured polycrystalline matrix. These abnormal grains grew rapidly and consumed the surrounding matrix. This bi-modal microstructure of the films affected the size and morphology of the particles formed at the late stages of dewetting. We demonstrated that the nucleation of abnormal grains and their growth are associated with the ordering reaction in Ni-Fe films, and the dependence of the alloy-sapphire interface energy on composition.
||Planned: Supplemental Proceedings volume