Interfacial strain evolution and abnormal Poisson's ratios in Al nuclei for the Al/TiB2 heterostructure. (15th July 2023)

• Record Type: Journal Article
• Authors: Feng, Jing; Han, Xiaocang; Han, Yanfeng; Wang, Xiaodong; Song, Shuangxi; Sun, Baode; Chen, Mingwei; Liu, Pan
• Is Part Of: Scripta materialia. Number 232(2023)
• Publication Date: 2023-07-15
• Subjects: Heterogeneous nucleation -- TiB2 particle -- Lattice mismatch -- Strain analysis -- Poisson's ratio; Materials -- Periodicals; Metallurgy -- Periodicals; Metalen; Legeringen; Materiaalkunde; Metals, metalworking and machinery industries; Metals; Electronic journals; 620.11
• DOI: 10.1016/j.scriptamat.2023.115508
• Languages: English
• ISSNs: 1359-6462

Abstract

Abstract: The interfacial lattice mismatch and local elastic strains of Al/TiB2 heterostructures are quantitatively investigated by aberration-corrected transmission electron microscopy. Both in-plane atomic expansion and out-of-plane compression of Al layers stacked on (0001)TiB2 are uncovered and favor the further extension of deformed Al layers for realizing a successfully heterogeneous nucleation. These lattice strains can persist up to several Al atomic layers from the topmost (0001) surface of TiB2 . Based on the compressive and expansive elastic strain relation, we estimate the Poisson's ratio in Al nuclei and find that large mismatch strains lead to abnormal changes in the Poisson's ratio. This study reveals the effect of lattice mismatch on the heterogeneous nucleation of Al on TiB2 and may have important implications in understanding the heterogeneous nucleation of Al. Graphical abstract: We reported the atomic-scale interfacial strain evolution of Al nucleation on selfformed TiB2 particles via in situ heating Cs-corrected transmission electron microscopy in amorphous Al-5Ti-1B film. Pure Al can directly nucleate on Ti-terminated {0001} TiB2 surfaces with a face-centered cubic {111} stacking and thus, the coherent lattice mismatch in Al/TiB2 interface leads to the formation of 7 strained Al layers. Such interfacial mismatch generates significant out-of-plane compressive and in-plane expansive strain in Al nuclei. Further, the abnormal Poisson's ratio changes in Al nuclei with a several-atomic-layer thickness originate from the interfacial compression strain effect. Our findings provide new atomic-scale insight into the interfacial behavior of Al/TiB2 heterostructure in the initial nucleation process and experimentally validate the strain-dependent Poisson's ratio in Al nuclei of several atomic layers thickness. Image, graphical abstract