Surface-Stress Induced Embrittlement of Metals

Udupa, A and Sugihara, T and Viswanathan, K and Latanision, RM and Chandrasekar, S (2021) Surface-Stress Induced Embrittlement of Metals. In: Nano Letters, 21 .

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Abstract

Environment-assisted fracture phenomena in metals are usually associated with surface energy reduction due to an adsorbed film. Here we demonstrate a unique embrittlement effect in Al that is instead mediated by surface stress, induced by an adsorbed organic monolayer. Atomistic simulations show that the adsorbate carbon-chain length lc controls the surface stress via van der Waals forces, being compressive for lc < 8 and tensile otherwise. For lc > 8, we demonstrate experimentally that the nanoscale film causes a ductile-to-brittle transition on the macroscale. Concomitant with this transition is a nearly 85 reduction in deformation forces. Additional simulations reveal that the microscopic mechanism for the embrittlement is via suppression of dislocation emission at incipient crack-tips. In addition to challenging long-held views on environment-assisted fracture, our findings pertaining to surface-stress induced embrittlement suggest profitable utility in manufacturing processes such as machining and comminution. © 2021 American Chemical Society.

Item Type:	Journal Article
Publication:	Nano Letters
Publisher:	American Chemical Society
Additional Information:	The copyright for this article belongs to American Chemical Society
Keywords:	Crack tips; Embrittlement; Surface stress; Van der Waals forces, Adsorbed films; Adsorbed organics; Atomistic simulations; Ductile brittle transition; Energy reduction; Environment-assisted cracking; Organic monolayers; Stress-induced; Surface plasticity; Surface stress, Monolayers
Department/Centre:	Division of Mechanical Sciences > Mechanical Engineering
Date Deposited:	31 Dec 2021 07:10
Last Modified:	31 Dec 2021 07:10
URI:	http://eprints.iisc.ac.in/id/eprint/70764

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