title: Thermostat Influence on the Structural Development and Material Removal during Abrasion of Nanocrystalline Ferrite.
abstract: We consider a nanomachining process of hard, abrasive particles grinding on the rough surface of a polycrystalline ferritic work piece. Using extensive large-scale molecular dynamics (MD) simulations, we show that the mode of thermostating, i.e., the way that the heat generated through deformation and friction is removed from the system, has crucial impact on tribological and materials related phenomena. By adopting an electron-phonon coupling approach to parametrize the thermostat of the system, thus including the electronic contribution to the thermal conductivity of iron, we can reproduce the experimentally measured values that yield realistic temperature gradients in the work piece. We compare these results to those obtained by assuming the two extreme cases of only phononic heat conduction and instantaneous removal of the heat generated in the machining interface. Our discussion of the differences between these three cases reveals that although the average shear stress is virtually temperature independent up to a normal pressure of approximately 1 GPa, the grain and chip morphology as well as most relevant quantities depend heavily on the mode of thermostating beyond a normal pressure of 0.4 GPa. These pronounced differences can be explained by the thermally activated processes that guide the reaction of the Fe lattice to the external mechanical and thermal loads caused by nanomachining.
authors.affiliation: AC2T research GmbH, Viktor-Kaplan-Straße 2, 2700 Wiener Neustadt, Austria.
authors.forename: Stefan J
authors.identifier: http://orcid.org/0000-0002-2902-3076
authors.initials: SJ
authors.lastname: Eder
authors.affiliation: AC2T research GmbH, Viktor-Kaplan-Straße 2, 2700 Wiener Neustadt, Austria.
authors.forename: Ulrike
authors.initials: U
authors.lastname: Cihak-Bayr
authors.affiliation: AC2T research GmbH, Viktor-Kaplan-Straße 2, 2700 Wiener Neustadt, Austria.
authors.forename: Davide
authors.initials: D
authors.lastname: Bianchi
authors.affiliation: Institute of Advanced Ceramics, Hamburg University of Technology , Denickestraße 15/K, 21073 Hamburg, Germany.
authors.forename: Gregor
authors.identifier: http://orcid.org/0000-0002-9327-0450
authors.initials: G
authors.lastname: Feldbauer
authors.affiliation: Institute of Applied Physics, Vienna University of Technology , Wiedner Hauptstraße 8-10/134, 1040 Vienna, Austria.
authors.forename: Gerhard
authors.initials: G
authors.lastname: Betz
keywords: abrasive wear; electron−phonon coupling; heat conductivity; molecular dynamics; nanomachining; polycrystal; thermostat