Journal article Open Access

In situ TEM observations on the structural evolution of a nanocrystalline W-Ti alloy at elevated temperatures

M. Callisti; T. Polcar; F.D. Tichelaar

The thermal stability and nanoscale structural evolution at elevated temperatures of a sputter deposited W-Ti alloy thin film were studied by a combination of ex situ and in situ techniques. XRD, FIB and SEM-EDX were used to characterise the film annealed ex situ in vacuum at 1373 K for 48 hrs. In situ TEM heating experiments were conducted at various temperatures up to 923 K to capture transitional phenomena occurring in the alloy upon heating and cooling. At a microscopic level, the alloy annealed at 1373 K for 48 hrs transformed from a single-phase β-(WTi) solid solution into a two-phase alloy consisting of Ti-rich grains in equilibrium with Ti-depleted β-(WTi) solid solution grains. In situ TEM observations revealed initial Ti segregations along columnar grain boundaries at T ~ 423 – 573 K, followed by Ti-rich clusters formation in the grains interior at T ~ 573 – 773 K. The microstructure observed at 923 K remained stable upon cooling to room temperature and consisted of Ti-rich segregations along the columnar grain boundaries and of alternate Ti-rich and Ti-depleted nanoscale domains in the grains interior, which formed a stable dual-phase nanocrystalline structure.

Files (5.8 MB)
Name Size
Manuscript_accepted (1).docx
md5:6d016d3e9bc0a9c49cca720c4aefc06f
5.8 MB Download
45
10
views
downloads
Views 45
Downloads 10
Data volume 58.4 MB
Unique views 41
Unique downloads 10

Share

Cite as