{"title":"In-situ observation of variant pair formation in bainite of low carbon steel by digital holographic microscopy","authors":"","doi":"10.1016/j.actamat.2024.120212","DOIUrl":null,"url":null,"abstract":"<div><p>Digital holographic microscopy (DHM) was employed to investigate the formation process and shape evolution of the most frequently observed bainite variant pairs in low-carbon alloy steel. Through in-situ observation coupled with theoretical predictions, the continuous changes in surface relief corresponding to bainite and adjacent austenite were measured. Additionally, the crystal orientations of the observed variant pairs were determined using electron backscattered diffraction (EBSD). The results indicated that at the onset of the transformation, the bainite variant shape agreed with theoretical predictions, while the adjacent austenite experienced plastic deformation. However, as the transformation proceeded towards completion, the shape of some bainite variants deviated from the theoretical predictions, while their adjacent austenite remained undeformed. This shift of deformation strain between austenite and bainite suggests a change in strain accommodation mechanism. Furthermore, the observed ‘tent-shaped’ surface relief was attributed to back-to-back mutually accommodating variant pairs, resulting in reduction of the total shape strain, compared to the theoretical prediction.</p></div>","PeriodicalId":238,"journal":{"name":"Acta Materialia","volume":null,"pages":null},"PeriodicalIF":8.3000,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1359645424005627/pdfft?md5=4edaab1663a46a7456631107f851ab38&pid=1-s2.0-S1359645424005627-main.pdf","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Acta Materialia","FirstCategoryId":"88","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S1359645424005627","RegionNum":1,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"MATERIALS SCIENCE, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
Abstract
Digital holographic microscopy (DHM) was employed to investigate the formation process and shape evolution of the most frequently observed bainite variant pairs in low-carbon alloy steel. Through in-situ observation coupled with theoretical predictions, the continuous changes in surface relief corresponding to bainite and adjacent austenite were measured. Additionally, the crystal orientations of the observed variant pairs were determined using electron backscattered diffraction (EBSD). The results indicated that at the onset of the transformation, the bainite variant shape agreed with theoretical predictions, while the adjacent austenite experienced plastic deformation. However, as the transformation proceeded towards completion, the shape of some bainite variants deviated from the theoretical predictions, while their adjacent austenite remained undeformed. This shift of deformation strain between austenite and bainite suggests a change in strain accommodation mechanism. Furthermore, the observed ‘tent-shaped’ surface relief was attributed to back-to-back mutually accommodating variant pairs, resulting in reduction of the total shape strain, compared to the theoretical prediction.
期刊介绍:
Acta Materialia serves as a platform for publishing full-length, original papers and commissioned overviews that contribute to a profound understanding of the correlation between the processing, structure, and properties of inorganic materials. The journal seeks papers with high impact potential or those that significantly propel the field forward. The scope includes the atomic and molecular arrangements, chemical and electronic structures, and microstructure of materials, focusing on their mechanical or functional behavior across all length scales, including nanostructures.