{
  "abstract": "Refractory body-centered cubic (BCC) alloys are attractive candidates for structural applications at extreme temperatures, yet combining room-temperature ductility with high-temperature strength remains the unsolved challenge. Ductility in crystals requires that dislocations emit from a sharp crack tip before brittle cleavage, but continuum theories that treat disordered alloys as chemically homogeneous incorrectly predict brittleness for many experimentally ductile alloys. Here we show that atomic-scale stress fluctuations in disordered alloys create an additional local stress intensity at the crack tip, enabling dislocation loop nucleation below the cleavage threshold. Accounting for these fluctuations yields a local ductility criterion where alloys deemed brittle by conventional fracture mechanics can be intrinsically ductile. Atomistic simulations with machine-learned interatomic potentials and an analytic fracture mechanics model correctly predict composition-driven brittle-to-ductile transitions in binary and ternary Mo-Nb-Ti alloys, in Nb-Ti alloys at 4 K, and in several commercial BCC alloys at room temperature. Guided by this criterion, we predict, fabricate, and test the Hf$_{15}$Mo$_{15}$Nb$_{32}$Ti$_{38}$ alloy, confirming its room-temperature ductility. This fluctuation-driven mechanism provides a quantitative basis for designing ductile multicomponent BCC alloys.",
  "abstract_shown": true,
  "affiliations": [],
  "article_type": null,
  "arxiv": "2609.13465",
  "author_total": 7,
  "authors": [
    {
      "name": "Manura Liyanage"
    },
    {
      "name": "Julia Chmielewska"
    },
    {
      "name": "Tijmen Vermeij"
    },
    {
      "name": "Johann Michler"
    },
    {
      "name": "Christian Leinenbach"
    },
    {
      "name": "W. A. Curtin"
    },
    {
      "name": "Anirudh Raju Natarajan"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/fsbs48d90e4q0.bib",
  "cited_by": 0,
  "doi": "10.48550/arxiv.2609.13465",
  "fulltext_url": null,
  "id": "fsbs48d90e4q0",
  "issns": [],
  "landing_url": "https://arxiv.org/abs/2609.13465",
  "language": null,
  "licence": "CC-BY-NC-ND-4.0",
  "licence_label": "CC BY-NC-ND 4.0",
  "licence_source": "article",
  "licence_url": "http://creativecommons.org/licenses/by-nc-nd/4.0/",
  "metadata_licence": "CC0-1.0",
  "native_subjects": [
    [
      "arxiv",
      "cond-mat.mtrl-sci"
    ],
    [
      "openalex",
      "2210|High Entropy Alloys Studies"
    ]
  ],
  "openalex": "W7213257536",
  "pdf_url": "https://arxiv.org/pdf/2609.13465",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-11",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/fsbs48d90e4q0.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:21:25Z",
      "native_id": "2609.13465",
      "source": "arxiv",
      "url": "https://arxiv.org/abs/2609.13465"
    }
  ],
  "subjects": [
    {
      "field": "physics",
      "origin": "arxiv:cond-mat.mtrl-sci",
      "subfield": "condensed-matter"
    }
  ],
  "title": "Cracking the case: fluctuations enhance ductility in refractory alloys",
  "title_text": "Cracking the case: fluctuations enhance ductility in refractory alloys",
  "type": "preprint",
  "updated_at": "2026-10-30T12:21:25Z",
  "url": "https://research.draconitic.com/paper/fsbs48d90e4q0",
  "venue": "arXiv",
  "versions": []
}