Brennan R. Watkins, C. Haas Blacksher, Alyssa Stubbers, Gregory B. Thompson, Christopher R. Weinberger
{"title":"位错迁移率对碳化钽异常硬度的洞察","authors":"Brennan R. Watkins, C. Haas Blacksher, Alyssa Stubbers, Gregory B. Thompson, Christopher R. Weinberger","doi":"10.1038/s41467-024-54893-9","DOIUrl":null,"url":null,"abstract":"<p>The tantalum carbides, TaC<sub><i>x</i></sub>, have been repeatedly shown to harden dramatically with some loss of carbon content, then soften with further decarburization. First observed in 1963, this anomalous hardness behavior has been reproduced for decades without satisfactory explanation. Prior attempts to characterize this phenomenon using elastic stiffnesses have failed to reproduce the anomalous hardness behavior. In this work, we demonstrate a change in slip system preference from {111}<sub>B1</sub> to {110}<sub>B1</sub> in TaC<sub><i>x</i></sub> as <i>x</i> decreases, while no such transition is observed in TiC<sub><i>x</i></sub>. We find this to be the primary mechanism of the anomalous hardness, arising from reduced energetic favorability of dissociation of dislocations on {111}<sub>B1</sub> into Shockley partials at lower carbon contents. We also present experimental hardness measurements for bulk and thin-film TaC<sub><i>x</i></sub> at different carbon contents. An anomalous hardness peak is observed in the bulk samples, but not in the thin films, due to loss of dislocation plasticity in the nanocrystalline films.</p>","PeriodicalId":19066,"journal":{"name":"Nature Communications","volume":"27 1","pages":""},"PeriodicalIF":15.7000,"publicationDate":"2024-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Insights into the anomalous hardness of the tantalum carbides from dislocation mobility\",\"authors\":\"Brennan R. Watkins, C. Haas Blacksher, Alyssa Stubbers, Gregory B. Thompson, Christopher R. Weinberger\",\"doi\":\"10.1038/s41467-024-54893-9\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p>The tantalum carbides, TaC<sub><i>x</i></sub>, have been repeatedly shown to harden dramatically with some loss of carbon content, then soften with further decarburization. First observed in 1963, this anomalous hardness behavior has been reproduced for decades without satisfactory explanation. Prior attempts to characterize this phenomenon using elastic stiffnesses have failed to reproduce the anomalous hardness behavior. In this work, we demonstrate a change in slip system preference from {111}<sub>B1</sub> to {110}<sub>B1</sub> in TaC<sub><i>x</i></sub> as <i>x</i> decreases, while no such transition is observed in TiC<sub><i>x</i></sub>. We find this to be the primary mechanism of the anomalous hardness, arising from reduced energetic favorability of dissociation of dislocations on {111}<sub>B1</sub> into Shockley partials at lower carbon contents. We also present experimental hardness measurements for bulk and thin-film TaC<sub><i>x</i></sub> at different carbon contents. An anomalous hardness peak is observed in the bulk samples, but not in the thin films, due to loss of dislocation plasticity in the nanocrystalline films.</p>\",\"PeriodicalId\":19066,\"journal\":{\"name\":\"Nature Communications\",\"volume\":\"27 1\",\"pages\":\"\"},\"PeriodicalIF\":15.7000,\"publicationDate\":\"2024-12-04\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Nature Communications\",\"FirstCategoryId\":\"103\",\"ListUrlMain\":\"https://doi.org/10.1038/s41467-024-54893-9\",\"RegionNum\":1,\"RegionCategory\":\"综合性期刊\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"MULTIDISCIPLINARY SCIENCES\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Nature Communications","FirstCategoryId":"103","ListUrlMain":"https://doi.org/10.1038/s41467-024-54893-9","RegionNum":1,"RegionCategory":"综合性期刊","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"MULTIDISCIPLINARY SCIENCES","Score":null,"Total":0}
Insights into the anomalous hardness of the tantalum carbides from dislocation mobility
The tantalum carbides, TaCx, have been repeatedly shown to harden dramatically with some loss of carbon content, then soften with further decarburization. First observed in 1963, this anomalous hardness behavior has been reproduced for decades without satisfactory explanation. Prior attempts to characterize this phenomenon using elastic stiffnesses have failed to reproduce the anomalous hardness behavior. In this work, we demonstrate a change in slip system preference from {111}B1 to {110}B1 in TaCx as x decreases, while no such transition is observed in TiCx. We find this to be the primary mechanism of the anomalous hardness, arising from reduced energetic favorability of dissociation of dislocations on {111}B1 into Shockley partials at lower carbon contents. We also present experimental hardness measurements for bulk and thin-film TaCx at different carbon contents. An anomalous hardness peak is observed in the bulk samples, but not in the thin films, due to loss of dislocation plasticity in the nanocrystalline films.
期刊介绍:
Nature Communications, an open-access journal, publishes high-quality research spanning all areas of the natural sciences. Papers featured in the journal showcase significant advances relevant to specialists in each respective field. With a 2-year impact factor of 16.6 (2022) and a median time of 8 days from submission to the first editorial decision, Nature Communications is committed to rapid dissemination of research findings. As a multidisciplinary journal, it welcomes contributions from biological, health, physical, chemical, Earth, social, mathematical, applied, and engineering sciences, aiming to highlight important breakthroughs within each domain.