Alexander Campos-Quiros, Metri Zughbi, Animesh Kundu, Masashi Watanabe
{"title":"铝酸镁尖晶石中钙、钇晶界偏析行为与断裂韧性增强的关系","authors":"Alexander Campos-Quiros, Metri Zughbi, Animesh Kundu, Masashi Watanabe","doi":"10.1007/s10853-024-10569-9","DOIUrl":null,"url":null,"abstract":"<div><p>Polycrystalline magnesium aluminate spinel, or simply spinel, with near theoretical density is a transparent ceramic material with multiple applications in extreme environmental conditions, which require an enhanced fracture toughness. For this reason, in this study, the effect of 500 ppm doping level of calcium (Ca) and yttrium (Y) on the segregation behavior and mechanical properties of spinel was quantitatively investigated. Calcium and yttrium doping reduced the grain-boundary plane anisotropy for grain boundaries with rotations about the [111] axis. More tilt boundaries and fewer twist boundaries were found in the doped samples compared to the undoped condition. Direct observations by high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) imaging revealed that yttrium atoms preferentially occupy aluminum sites at grain boundaries in spinel. Quantitative electron energy-loss spectrometry (EELS) analysis in the vicinity of grain boundaries indicated that calcium atoms preferentially occupy magnesium sites in the Ca-doped spinel samples and confirmed the substitution of aluminum by yttrium atoms in the Y-doped sample. Quantitative X-ray energy-dispersive spectrometry (XEDS) analysis employing the ζ-factor method indicated that the maximum segregation levels at grain boundaries were 0.8 ± 0.1 calcium atoms/nm<sup>2</sup> (0.23 ± 0.03 monolayers) and 2.4 ± 0.06 yttrium atoms/nm<sup>2</sup> (0.45 ± 0.11 monolayers). Enhanced indentation fracture toughness was found in samples with calcium and yttrium doping compared to undoped spinel. The enhanced fracture toughness in Ca- and Y-doped spinel samples, in comparison with undoped spinel, was primarily attributed to more pronounced crack deflections and a more tortuous crack path.</p><h3>Graphical abstract</h3>\n<div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":645,"journal":{"name":"Journal of Materials Science","volume":"60 4","pages":"1826 - 1852"},"PeriodicalIF":3.5000,"publicationDate":"2025-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Correlation between grain-boundary segregation behaviors of calcium and yttrium and enhanced fracture toughness in magnesium aluminate spinel\",\"authors\":\"Alexander Campos-Quiros, Metri Zughbi, Animesh Kundu, Masashi Watanabe\",\"doi\":\"10.1007/s10853-024-10569-9\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>Polycrystalline magnesium aluminate spinel, or simply spinel, with near theoretical density is a transparent ceramic material with multiple applications in extreme environmental conditions, which require an enhanced fracture toughness. For this reason, in this study, the effect of 500 ppm doping level of calcium (Ca) and yttrium (Y) on the segregation behavior and mechanical properties of spinel was quantitatively investigated. Calcium and yttrium doping reduced the grain-boundary plane anisotropy for grain boundaries with rotations about the [111] axis. More tilt boundaries and fewer twist boundaries were found in the doped samples compared to the undoped condition. Direct observations by high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) imaging revealed that yttrium atoms preferentially occupy aluminum sites at grain boundaries in spinel. Quantitative electron energy-loss spectrometry (EELS) analysis in the vicinity of grain boundaries indicated that calcium atoms preferentially occupy magnesium sites in the Ca-doped spinel samples and confirmed the substitution of aluminum by yttrium atoms in the Y-doped sample. Quantitative X-ray energy-dispersive spectrometry (XEDS) analysis employing the ζ-factor method indicated that the maximum segregation levels at grain boundaries were 0.8 ± 0.1 calcium atoms/nm<sup>2</sup> (0.23 ± 0.03 monolayers) and 2.4 ± 0.06 yttrium atoms/nm<sup>2</sup> (0.45 ± 0.11 monolayers). Enhanced indentation fracture toughness was found in samples with calcium and yttrium doping compared to undoped spinel. The enhanced fracture toughness in Ca- and Y-doped spinel samples, in comparison with undoped spinel, was primarily attributed to more pronounced crack deflections and a more tortuous crack path.</p><h3>Graphical abstract</h3>\\n<div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>\",\"PeriodicalId\":645,\"journal\":{\"name\":\"Journal of Materials Science\",\"volume\":\"60 4\",\"pages\":\"1826 - 1852\"},\"PeriodicalIF\":3.5000,\"publicationDate\":\"2025-01-03\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of Materials Science\",\"FirstCategoryId\":\"88\",\"ListUrlMain\":\"https://link.springer.com/article/10.1007/s10853-024-10569-9\",\"RegionNum\":3,\"RegionCategory\":\"材料科学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"MATERIALS SCIENCE, MULTIDISCIPLINARY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Materials Science","FirstCategoryId":"88","ListUrlMain":"https://link.springer.com/article/10.1007/s10853-024-10569-9","RegionNum":3,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"MATERIALS SCIENCE, MULTIDISCIPLINARY","Score":null,"Total":0}
Correlation between grain-boundary segregation behaviors of calcium and yttrium and enhanced fracture toughness in magnesium aluminate spinel
Polycrystalline magnesium aluminate spinel, or simply spinel, with near theoretical density is a transparent ceramic material with multiple applications in extreme environmental conditions, which require an enhanced fracture toughness. For this reason, in this study, the effect of 500 ppm doping level of calcium (Ca) and yttrium (Y) on the segregation behavior and mechanical properties of spinel was quantitatively investigated. Calcium and yttrium doping reduced the grain-boundary plane anisotropy for grain boundaries with rotations about the [111] axis. More tilt boundaries and fewer twist boundaries were found in the doped samples compared to the undoped condition. Direct observations by high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) imaging revealed that yttrium atoms preferentially occupy aluminum sites at grain boundaries in spinel. Quantitative electron energy-loss spectrometry (EELS) analysis in the vicinity of grain boundaries indicated that calcium atoms preferentially occupy magnesium sites in the Ca-doped spinel samples and confirmed the substitution of aluminum by yttrium atoms in the Y-doped sample. Quantitative X-ray energy-dispersive spectrometry (XEDS) analysis employing the ζ-factor method indicated that the maximum segregation levels at grain boundaries were 0.8 ± 0.1 calcium atoms/nm2 (0.23 ± 0.03 monolayers) and 2.4 ± 0.06 yttrium atoms/nm2 (0.45 ± 0.11 monolayers). Enhanced indentation fracture toughness was found in samples with calcium and yttrium doping compared to undoped spinel. The enhanced fracture toughness in Ca- and Y-doped spinel samples, in comparison with undoped spinel, was primarily attributed to more pronounced crack deflections and a more tortuous crack path.
期刊介绍：
The Journal of Materials Science publishes reviews, full-length papers, and short Communications recording original research results on, or techniques for studying the relationship between structure, properties, and uses of materials. The subjects are seen from international and interdisciplinary perspectives covering areas including metals, ceramics, glasses, polymers, electrical materials, composite materials, fibers, nanostructured materials, nanocomposites, and biological and biomedical materials. The Journal of Materials Science is now firmly established as the leading source of primary communication for scientists investigating the structure and properties of all engineering materials.
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