https://doi.org/10.1140/epjp/s13360-026-07375-4
Regular Article
Microscopic mechanism for the effect of Bi particle inclusion configurations on drilling behavior of polycrystalline FeNiCr alloys: a molecular dynamics study
School of Mechanical and Electrical Engineering, Xi’an University of Architecture and Technology, 710055, Xi’an, China
a
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Received:
1
November
2025
Accepted:
26
January
2026
Published online:
9
February
2026
Abstract
As an environmentally friendly substitute for Pb, Bi has been increasingly applied in free-cutting steels; however, the atomic-scale mechanisms by which Bi influences machining behavior remain unclear. This study aims to investigate how the spatial configurations of Bi inclusions affect the drilling performance of polycrystalline FeNiCr alloys. It is hypothesized that different spatial contact modes between the drill bit and Bi inclusions alter the mechanical response of the matrix and the accumulation of subsurface damage. To this end, a molecular dynamics (MD) model is developed, in which a twist-drill geometry is innovatively introduced to realistically simulate the chip evacuation process. Three representative interaction configurations—intersection, tangency, and separation—are systematically compared. The results demonstrate that the inclusion position significantly influences cutting force, stress distribution, dislocation evolution, thermo-mechanical response, and microscopic deformation behavior. Specifically, the intersection configuration markedly reduces drilling resistance, exhibits a stronger capability to alleviate stress concentration, and effectively suppresses the long-range glide of Shockley partial dislocations, whereas the effects of the tangency and separation configurations are limited. Moreover, compared with the tangency and separation configurations, the intersection configuration further reduces matrix temperature rise and strain accumulation through plastic dissipation and the metallic lubrication effect of the Bi particles. This work elucidates the regulatory role of Bi particle positioning on internal microstructural evolution and provides theoretical guidance for optimizing microstructural design and machining quality of Bi-containing alloys.
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© The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2026
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
