{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,9]],"date-time":"2026-07-09T14:20:08Z","timestamp":1783606808440,"version":"3.55.0"},"reference-count":18,"publisher":"MDPI AG","issue":"21","license":[{"start":{"date-parts":[[2024,10,22]],"date-time":"2024-10-22T00:00:00Z","timestamp":1729555200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Department of Energy-National Nuclear Security Administration (DOE-NNSA), Stewardship Science Academic Program","award":["DE-NA0003857"],"award-info":[{"award-number":["DE-NA0003857"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Materials"],"abstract":"<jats:p>A thorough procedure was developed to efficiently manufacture dogbone samples using focused ion beam (FIB) milling for micro-tensile testing. A Bruker PI 89 PicoIndenter, Billerica, MA, USA, was used as a case study, although the analysis and results are applicable to other micro-mechanical testing systems capable of mounting a standard, \u00d812.7 mm \u00d7 \u00d83.2 mm pin, scanning electron microscopy (SEM) pin stub (Ted Pella, Redding, CA, USA). Nine dogbones were made from an Fe-45Cu alloy additively manufactured using powder-fed laser-directed energy deposition (DED-LB). Testing showed that fracture was confined to the gauge section for all dogbones and that the fracture mode, ductile vs. brittle, was entirely dependent on the grain orientation relative to the loading direction. The analysis showed that the measured plastic strain to failure can vary from &gt;11% (optimal geometry) to &lt;1% (non-optimal geometry) in micro-tensile testing of high-tensile-strength (&gt;1 GPa) metallic materials. Subsequently, a finite element analysis (FEA) was conducted to identify the improved dogbone geometries. A total of ten thousand dogbone geometries were tested, and their dimensions were defined by a set of four adjustable parameters (corner radius, load surface angle, load surface length, and dogbone head length). The gauge width and gauge length were fixed to 4 \u00b5m and 10 \u00b5m, respectively. Three-dimensional surface plots of the stress concentration as a function of two parameters were used to identify the optimal ranges of parameter values. The addition of maximum width and length constraints, measuring 25 \u00b5m and 30 \u00b5m, respectively, allowed us to identify an optimal geometry at load surface angles of 30\u00b0 and 45\u00b0. Their respective dimensions (corner radius, load surface length, and dogbone head length) are, in \u00b5m, 12, 6, and 7 and 10, 7, and 7. Testing these two optimal geometries with a range of gauge lengths from 4 to 20 \u00b5m showed that smaller gauge lengths only slightly reduced the detrimental stress concentration outside the gauge section. However, smaller gauge lengths will notably improve the FIB surface polishing step as tapering is reduced with smaller dogbone lengths.<\/jats:p>","DOI":"10.3390\/ma17215144","type":"journal-article","created":{"date-parts":[[2024,10,22]],"date-time":"2024-10-22T11:31:57Z","timestamp":1729596717000},"page":"5144","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["Optimal Geometry for Focused Ion Beam-Milled Samples for Direct-Pull Micro-Tensile Testing Performed In Situ in a Scanning Electron Microscope"],"prefix":"10.3390","volume":"17","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-6898-1218","authenticated-orcid":false,"given":"Daniel B.","family":"Yin","sequence":"first","affiliation":[{"name":"Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI 48109, USA"},{"name":"Sigma Division, Los Alamos National Laboratory, Los Alamos, NM 87545, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0006-5328-7342","authenticated-orcid":false,"given":"Haiping","family":"Sun","sequence":"additional","affiliation":[{"name":"Michigan Center for Materials Characterization, University of Michigan, Ann Arbor, MI 48109, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3634-6823","authenticated-orcid":false,"given":"Amit","family":"Misra","sequence":"additional","affiliation":[{"name":"Department of Materials Science and Engineering, University of Michigan, Ann Arbor, MI 48109, USA"},{"name":"Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI 48109, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2024,10,22]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"214","DOI":"10.1557\/s43577-023-00643-z","article-title":"Nanomechanical characterization","volume":"49","author":"Kiener","year":"2024","journal-title":"MRS Bull."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"580","DOI":"10.1016\/j.actamat.2007.10.015","article-title":"A further step towards an understanding of size-dependent crystal plasticity: In situ tension experiments of miniaturized single-crystal copper samples","volume":"56","author":"Kiener","year":"2008","journal-title":"Acta Mater."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"609","DOI":"10.1038\/ncomms1619","article-title":"Approaching the ideal elastic limit of metallic glasses","volume":"3","author":"Tian","year":"2012","journal-title":"Nat. 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