{"title":"受变形驱动相变影响的重载曲线钢轨流唇的微结构和元素分析","authors":"Sudharm Rathore , Soumyajit Mojumder , Cong Qiu , Peter Mutton , Aparna Singh","doi":"10.1016/j.wear.2024.205462","DOIUrl":null,"url":null,"abstract":"<div><p>A combination of optical imaging (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and atom probe tomography (APT) was used to examine the white etching layer (WEL) and brown etching layer (BEL) formed in the flow lip region of a heavy haul curved rail. These flow lips eventually serve as crack initiating regions, leading to reverse detail fractures. OM distinctly identified the WEL/BEL region based on light contrast, while SEM micrographs identified a fine-grained structure within the WEL with intermittent patches of a deformed pearlitic structure. SEM images of the WEL/BEL indicate that the fraction of cementite patches was higher in the BEL region than in the WEL. TEM investigations revealed the presence of martensite/nano-crystalline ferrite along with newly formed austenite and cementite particles in the WEL and the BEL. The ferrite/martensite grain size was much finer in the WEL than in the BEL. The lath morphology of martensite was observed in the BEL, whereas a mixed morphology of lath and twinned martensite was observed in the WEL. APT studies show no Mn/Si partitioning in WEL/BEL along with C-concentrations ranging from 10 to 15 at.% and up to 20 at.% in the WEL and BEL respectively. The synergistic effect of elevated wheel-rail contact temperatures and severe plastic deformation dictated the overall microstructural evolution of the BELs and WELs on the outer rail surface in the flow lip.</p></div>","PeriodicalId":23970,"journal":{"name":"Wear","volume":null,"pages":null},"PeriodicalIF":5.3000,"publicationDate":"2024-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Microstructural and elemental analysis of flow lips of heavy haul curved rails affected by deformation driven phase transformation\",\"authors\":\"Sudharm Rathore , Soumyajit Mojumder , Cong Qiu , Peter Mutton , Aparna Singh\",\"doi\":\"10.1016/j.wear.2024.205462\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>A combination of optical imaging (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and atom probe tomography (APT) was used to examine the white etching layer (WEL) and brown etching layer (BEL) formed in the flow lip region of a heavy haul curved rail. These flow lips eventually serve as crack initiating regions, leading to reverse detail fractures. OM distinctly identified the WEL/BEL region based on light contrast, while SEM micrographs identified a fine-grained structure within the WEL with intermittent patches of a deformed pearlitic structure. SEM images of the WEL/BEL indicate that the fraction of cementite patches was higher in the BEL region than in the WEL. TEM investigations revealed the presence of martensite/nano-crystalline ferrite along with newly formed austenite and cementite particles in the WEL and the BEL. The ferrite/martensite grain size was much finer in the WEL than in the BEL. The lath morphology of martensite was observed in the BEL, whereas a mixed morphology of lath and twinned martensite was observed in the WEL. APT studies show no Mn/Si partitioning in WEL/BEL along with C-concentrations ranging from 10 to 15 at.% and up to 20 at.% in the WEL and BEL respectively. The synergistic effect of elevated wheel-rail contact temperatures and severe plastic deformation dictated the overall microstructural evolution of the BELs and WELs on the outer rail surface in the flow lip.</p></div>\",\"PeriodicalId\":23970,\"journal\":{\"name\":\"Wear\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":5.3000,\"publicationDate\":\"2024-06-22\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Wear\",\"FirstCategoryId\":\"5\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0043164824002278\",\"RegionNum\":1,\"RegionCategory\":\"工程技术\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"ENGINEERING, MECHANICAL\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Wear","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0043164824002278","RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ENGINEERING, MECHANICAL","Score":null,"Total":0}
引用次数: 0
摘要
采用光学成像 (OM)、扫描电子显微镜 (SEM)、透射电子显微镜 (TEM) 和原子探针层析成像 (APT) 技术,对重载曲线钢轨流唇区形成的白色蚀刻层 (WEL) 和棕色蚀刻层 (BEL) 进行了检测。这些流唇最终会成为裂纹起始区,导致反向细节断裂。根据光对比度,OM 可明显识别出 WEL/BEL 区域,而 SEM 显微照片则可识别出 WEL 内的细粒结构,以及间歇性的变形珠光体结构斑块。WEL/BEL 的扫描电镜图像显示,BEL 区域的雪明碳酸盐斑块比例高于 WEL。TEM 研究显示,在 WEL 和 BEL 中存在马氏体/纳米晶铁素体以及新形成的奥氏体和雪明碳铁颗粒。WEL 中的铁素体/马氏体晶粒比 BEL 中的要细得多。在 BEL 中观察到马氏体的板条形态,而在 WEL 中观察到板条和孪晶马氏体的混合形态。APT 研究表明,WEL/BEL 中没有锰/硅分区,而 WEL 和 BEL 中的 C 浓度分别为 10 至 15 % 和高达 20 %。轮轨接触温度升高和剧烈塑性变形的协同作用决定了流唇中外轨表面 BEL 和 WEL 的整体微观结构演变。
Microstructural and elemental analysis of flow lips of heavy haul curved rails affected by deformation driven phase transformation
A combination of optical imaging (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and atom probe tomography (APT) was used to examine the white etching layer (WEL) and brown etching layer (BEL) formed in the flow lip region of a heavy haul curved rail. These flow lips eventually serve as crack initiating regions, leading to reverse detail fractures. OM distinctly identified the WEL/BEL region based on light contrast, while SEM micrographs identified a fine-grained structure within the WEL with intermittent patches of a deformed pearlitic structure. SEM images of the WEL/BEL indicate that the fraction of cementite patches was higher in the BEL region than in the WEL. TEM investigations revealed the presence of martensite/nano-crystalline ferrite along with newly formed austenite and cementite particles in the WEL and the BEL. The ferrite/martensite grain size was much finer in the WEL than in the BEL. The lath morphology of martensite was observed in the BEL, whereas a mixed morphology of lath and twinned martensite was observed in the WEL. APT studies show no Mn/Si partitioning in WEL/BEL along with C-concentrations ranging from 10 to 15 at.% and up to 20 at.% in the WEL and BEL respectively. The synergistic effect of elevated wheel-rail contact temperatures and severe plastic deformation dictated the overall microstructural evolution of the BELs and WELs on the outer rail surface in the flow lip.
期刊介绍:
Wear journal is dedicated to the advancement of basic and applied knowledge concerning the nature of wear of materials. Broadly, topics of interest range from development of fundamental understanding of the mechanisms of wear to innovative solutions to practical engineering problems. Authors of experimental studies are expected to comment on the repeatability of the data, and whenever possible, conduct multiple measurements under similar testing conditions. Further, Wear embraces the highest standards of professional ethics, and the detection of matching content, either in written or graphical form, from other publications by the current authors or by others, may result in rejection.