2021/11/08 by Vivek Devulapalli, Devulapalli, Vivek, Marcus Hans +9
Engineering · Materials Science · #Advanced Materials Characterization Techniques #FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci) #Metal and Thin Film Mechanics #Microstructure and mechanical properties
paper · pdf · doi:10.48550/arxiv.2111.04606
openalex publication_date 2021/11/08 · openalex created_date 2022/07/25 · openalex updated_date 2026/07/28
The structure and chemistry of grain boundaries (GBs) are crucial in determining polycrystalline materials' properties. Faceting and solute segregation to minimize the GB energy is a commonly observed phenomenon. In this paper, a deposition process to obtain pure tilt GBs in titanium (Ti) thin films is presented. By increasing the power density, a transition from polycrystalline film growth to a maze bicrystalline Ti film on SrTiO3 (001) substrate is triggered. All the GBs in the bicrystalline thin film are characterized to be Σ13 [0001] coincident site lattice (CSL) boundaries. The GB planes are seen to distinctly facet into symmetric 7520 and asymmetric 1010 // 1120 segments of 20-50~nm length. Additionally, EDS reveals preferential segregation of iron (Fe) in every alternate symmetric 7520 segment. Both the faceting and the segregation are explained by a difference in the CSL density between the facet planes. Furthermore, in the GB plane containing Fe segregation, atom probe tomography is used to experimentally determine the GB excess solute to be 1.25~atoms/nm2. In summary, the study reveals for the first time a methodology to obtain bicrystalline Ti thin films with strong faceting and anisotropy in iron (Fe) segregation behaviour within the same family of planes.