PSI - Issue 61

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ScienceDirect

Procedia Structural Integrity 61 (2024) 34–41 Structural Integrity Procedia 00 (2024) 000–000 Structural Integrity Procedia 00 (2024) 000–000

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© 2024 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the scientific committee of IWPDF 2023 Chairman Abstract Nanoscratch testing is a method pivotal for evaluating the mechanical and tribological characteristics of materials which involves the controlled scratching of specimens with a nano-scale indenter. This research delves into the analysis of e ff ect of grain size on the deformation mechanisms and material responses during nanoscratch tests on polycrystalline copper. By utilizing finite element method and adopting a lower-order strain gradient crystal plasticity framework, this study investigates results such as reaction forces on the indenter, apparent friction coe ffi cients, and alterations in pile-up topography. These factors are examined with the aforementioned strain gradient theory, employing calculations of the density of geometrically necessary dislocations to obtain size-dependent material response. The crystal plasticity framework is implemented into ABAQUS as a user material subroutine (UMAT), and the model’s accuracy is a ffi rmed through comparisons with experimental data from single crystal copper studies available in the literature. 3D geometries are generated to model a single crystal and three polycrystal materials with average grain diameters of 5 µ m , 15 µ m , and 50 µ m . These specimens are subjected to deformation by a rigid Berkovich indenter to simulate nanoscratching tests in the numerical examples, where the key point is to examine the grain size e ff ects while keeping fixed any other variables that may influence the results. © 2024 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http: // creativecommons.org / licenses / by-nc-nd / 4.0 / ) Peer-review under responsibility of the scientific committee of IWPDF 2023. Keywords: crystal plasticity; finite element method; nanoscratching; size e ff ects 3rd International Workshop on Plasticity, Damage and Fracture of Engineering Materials (IWPDF 2023) Nanoscratching of polycrystalline copper examined through strain gradient crystal plasticity Enes Gu¨nay, Merthan O¨ zdemir, Tuncay Yalc¸inkaya ∗ Department of Aerospace Engineering, Middle East Technical University, Ankara 06800, Tu¨rkiye Abstract Nanoscratch testing is a method pivotal for evaluating the mechanical and tribological characteristics of materials which involves the controlled scratching of specimens with a nano-scale indenter. This research delves into the analysis of e ff ect of grain size on the deformation mechanisms and material responses during nanoscratch tests on polycrystalline copper. By utilizing finite element method and adopting a lower-order strain gradient crystal plasticity framework, this study investigates results such as reaction forces on the indenter, apparent friction coe ffi cients, and alterations in pile-up topography. These factors are examined with the aforementioned strain gradient theory, employing calculations of the density of geometrically necessary dislocations to obtain size-dependent material response. The crystal plasticity framework is implemented into ABAQUS as a user material subroutine (UMAT), and the model’s accuracy is a ffi rmed through comparisons with experimental data from single crystal copper studies available in the literature. 3D geometries are generated to model a single crystal and three polycrystal materials with average grain diameters of 5 µ m , 15 µ m , and 50 µ m . These specimens are subjected to deformation by a rigid Berkovich indenter to simulate nanoscratching tests in the numerical examples, where the key point is to examine the grain size e ff ects while keeping fixed any other variables that may influence the results. © 2024 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http: // creativecommons.org / licenses / by-nc-nd / 4.0 / ) Peer-review under responsibility of the scientific committee of IWPDF 2023. Keywords: crystal plasticity; finite element method; nanoscratching; size e ff ects 3rd International Workshop on Plasticity, Damage and Fracture of Engineering Materials (IWPDF 2023) Nanoscratching of polycrystalline copper examined through strain gradient crystal plasticity Enes Gu¨nay, Merthan O¨ zdemir, Tuncay Yalc¸inkaya ∗ Department of Aerospace Engineering, Middle East Technical University, Ankara 06800, Tu¨rkiye

1. Introduction 1. Introduction

Nanoscratching is a technique that has been used to investigate mechanical characteristics of materials, such as failure behaviour, adhesion strength, friction, wear resistance, and hardness (see e.g., Wang et al. (2019a)). This technique is applicable to various specimen types, such as metals, alloys, thin films, ceramics, surface coatings, and MEMS. The deformation resulting from these tests are on nano- or micron-scale, where the geometrical characteristics of grains become an influencing factor for the results. Nanoscratching is a technique that has been used to investigate mechanical characteristics of materials, such as failure behaviour, adhesion strength, friction, wear resistance, and hardness (see e.g., Wang et al. (2019a)). This technique is applicable to various specimen types, such as metals, alloys, thin films, ceramics, surface coatings, and MEMS. The deformation resulting from these tests are on nano- or micron-scale, where the geometrical characteristics of grains become an influencing factor for the results.

∗ Corresponding author. E-mail address: yalcinka@metu.edu.tr ∗ Corresponding author. E-mail address: yalcinka@metu.edu.tr

2452-3216 © 2024 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the scientific committee of IWPDF 2023 Chairman 10.1016/j.prostr.2024.06.006 2210-7843 © 2024 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http: // creativecommons.org / licenses / by-nc-nd / 4.0 / ) Peer-review under responsibility of the scientific committee of IWPDF 2023. 2210-7843 2024 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http: // creativecommons.org / licenses / by-nc-nd / 4.0 / ) Peer-review under responsibility of the scientific committee of IWPDF 2023.