The principle, imaging condition and experimental method for obtaining high resolution composition contrast in secondary electron image were described. A new technique of specimen preparation for secondary electron co...The principle, imaging condition and experimental method for obtaining high resolution composition contrast in secondary electron image were described. A new technique of specimen preparation for secondary electron composition contrast observation was introduced and discussed. By using multilayer P+Si1-xGex/pSi heterojunction internal photoemission infrared detector as an example, the applications of secondary electron composition contrast imaging in microstructure studies on heterojunction semiconducting materials and devices were stated. The characteristics of the image were compared with the ordinary transmission electron diffraction contrast image. The prospects of applications of the imaging method in heterojunction semiconductor devices and multilayer materials are also discussed.展开更多
In the field of materials science,Electron Backscatter Diffraction(EBSD)technology has become a powerful tool for microstructure analysis,demonstrating unique advantages in the study of material texture,grain size,and...In the field of materials science,Electron Backscatter Diffraction(EBSD)technology has become a powerful tool for microstructure analysis,demonstrating unique advantages in the study of material texture,grain size,and orientation distribution.Recognizing that the quality of EBSD sample preparation directly impacts the accuracy and reliability of data,this paper delves into the principles of EBSD technology and explores optimized methodologies for sample preparation.By examining the influence of different preparation techniques on EBSD data quality,this study systematically summarizes best practices for critical steps such as surface treatment,polishing,and electrolytic polishing.The research reveals that meticulous sample preparation significantly enhances the quality of EBSD images,thereby improving the resolution and precision of diffraction data.Additionally,addressing the challenges and limitations encountered in practical applications of EBSD technology,a series of improvement measures are proposed to facilitate the widespread application of EBSD in materials science.In summary,this paper aims to provide researchers with a comprehensive EBSD sample preparation guideline,fostering advanced research and practical applications in the field of material analysis.展开更多
The microstructure development of 55VNb1 microalloyed steel after warm deformation via multi-pass biaxial compression tests was studied,and the effect of thermomechanical conditions on spheroidisation of cementite lam...The microstructure development of 55VNb1 microalloyed steel after warm deformation via multi-pass biaxial compression tests was studied,and the effect of thermomechanical conditions on spheroidisation of cementite lamellae and ferrite recrystallisation for a range of deformation temperatures(600–700℃),cooling/soaking time(water quenching,air cooling,10 and 30 min of soaking time)and interpass time(0–10 s)was analysed.During deformation,the spheroidisation of pearlite is dynamically accelerated mainly by boundary splitting mechanism together with the rapid dissolution of cementite,while ferrite softening is attributed to dynamic recovery and continuous dynamic recrystallisation.The strong microstructural evolution during cooling/soaking time indicates that deformation energy accumulated is sufficient to activate metallurgical phenomena in both phases also statically.Static spheroidisation is a diffusive process,with rate controlled by the diffusion of vacancies,as suggested by the estimated activation energy.Ferrite refinement is the result of the evolution of continuous recrystallisation and pinning effect exerted by fine,globulised and homogeneously dispersed cementite particles.Increasing temperature causes accelerated kinetics in metallurgical phenomena;therefore,cooling/soaking time becomes key parameters to achieve ultrafine grained and spheroidised microstructures.Interpass time favours spheroidisation and promotes continuous recrystallisation;however,it must be carefully controlled to find a balance between recrystallisation and Ostwald ripening to optimise microstructural development.展开更多
背散射电子(BSE)与能量色散X射线谱(EDS)图像分析技术凭借其出色的二维空间分辨能力,已成为表征土木工程材料微观结构的重要技术手段。本工作提出一种标准化的图像预处理策略,通过整合BSE图像和同视场的定性与定量EDS元素面谱,建立以超...背散射电子(BSE)与能量色散X射线谱(EDS)图像分析技术凭借其出色的二维空间分辨能力,已成为表征土木工程材料微观结构的重要技术手段。本工作提出一种标准化的图像预处理策略,通过整合BSE图像和同视场的定性与定量EDS元素面谱,建立以超像素为基本分析单元的多模态数据集,有效克服孔隙存在及特征X射线与样品相互作用体积过大对物相识别的影响。结合降维和聚类算法,开发可解释的BSE-EDS图像分析模型,实现水泥矿渣复合胶凝体系物相组成的自动化分类。基于Glue平台构建多视图交互分析技术,实现化学元素特征、物相含量分布和离子迁移路径的可视化、同步、联动表征。基于PHATE(Potential of heat-diffusion for affinity-based trajectory embedding)图像构建物相网络拓扑图,通过节点-连接拓扑关系量化物相演化动态特征。最终形成以EDS图像为核心、BSE图像为辅助的智能分析范式,实现化学模态(元素组成、物相类别)与空间模态(孔隙分布、物相分布)的协同定量表征,达成“单次独立微观表征-多模态特征融合分析”的技术愿景,为胶凝体系反应机理研究及微观结构动态演化分析提供较为综合全面的技术支撑。展开更多
In this study, the allotropic phase transition and its effect on the magnetic behavior of Fe Co–7 wt%V alloy were investigated. It was found that c phase is observed in the microstructure in the as-cast condition, an...In this study, the allotropic phase transition and its effect on the magnetic behavior of Fe Co–7 wt%V alloy were investigated. It was found that c phase is observed in the microstructure in the as-cast condition, and it diminishes after severe cold rolling（90% reduction）. After annealing at temperatures higher than 500 up to 750 ℃, the c phase is observed in the structure, again. But, this phase is disappeared by annealing at temperatures above 750 ℃ due to the formation of vanadium-rich precipitates. Thermocalc software was used in order to elucidate the influence of vanadium percent on the stability of c phase in Fe–Co alloys. Also, magnetic studies showed that the saturation induction is reduced by annealing at temperatures from 500 up to 750 ℃, which is related to the formation of residual non-magnetic γ phase.展开更多
文摘The principle, imaging condition and experimental method for obtaining high resolution composition contrast in secondary electron image were described. A new technique of specimen preparation for secondary electron composition contrast observation was introduced and discussed. By using multilayer P+Si1-xGex/pSi heterojunction internal photoemission infrared detector as an example, the applications of secondary electron composition contrast imaging in microstructure studies on heterojunction semiconducting materials and devices were stated. The characteristics of the image were compared with the ordinary transmission electron diffraction contrast image. The prospects of applications of the imaging method in heterojunction semiconductor devices and multilayer materials are also discussed.
文摘In the field of materials science,Electron Backscatter Diffraction(EBSD)technology has become a powerful tool for microstructure analysis,demonstrating unique advantages in the study of material texture,grain size,and orientation distribution.Recognizing that the quality of EBSD sample preparation directly impacts the accuracy and reliability of data,this paper delves into the principles of EBSD technology and explores optimized methodologies for sample preparation.By examining the influence of different preparation techniques on EBSD data quality,this study systematically summarizes best practices for critical steps such as surface treatment,polishing,and electrolytic polishing.The research reveals that meticulous sample preparation significantly enhances the quality of EBSD images,thereby improving the resolution and precision of diffraction data.Additionally,addressing the challenges and limitations encountered in practical applications of EBSD technology,a series of improvement measures are proposed to facilitate the widespread application of EBSD in materials science.In summary,this paper aims to provide researchers with a comprehensive EBSD sample preparation guideline,fostering advanced research and practical applications in the field of material analysis.
基金financially supported by the European Coal and Steel Community(RFCS-2015.No.709828).
文摘The microstructure development of 55VNb1 microalloyed steel after warm deformation via multi-pass biaxial compression tests was studied,and the effect of thermomechanical conditions on spheroidisation of cementite lamellae and ferrite recrystallisation for a range of deformation temperatures(600–700℃),cooling/soaking time(water quenching,air cooling,10 and 30 min of soaking time)and interpass time(0–10 s)was analysed.During deformation,the spheroidisation of pearlite is dynamically accelerated mainly by boundary splitting mechanism together with the rapid dissolution of cementite,while ferrite softening is attributed to dynamic recovery and continuous dynamic recrystallisation.The strong microstructural evolution during cooling/soaking time indicates that deformation energy accumulated is sufficient to activate metallurgical phenomena in both phases also statically.Static spheroidisation is a diffusive process,with rate controlled by the diffusion of vacancies,as suggested by the estimated activation energy.Ferrite refinement is the result of the evolution of continuous recrystallisation and pinning effect exerted by fine,globulised and homogeneously dispersed cementite particles.Increasing temperature causes accelerated kinetics in metallurgical phenomena;therefore,cooling/soaking time becomes key parameters to achieve ultrafine grained and spheroidised microstructures.Interpass time favours spheroidisation and promotes continuous recrystallisation;however,it must be carefully controlled to find a balance between recrystallisation and Ostwald ripening to optimise microstructural development.
文摘背散射电子(BSE)与能量色散X射线谱(EDS)图像分析技术凭借其出色的二维空间分辨能力,已成为表征土木工程材料微观结构的重要技术手段。本工作提出一种标准化的图像预处理策略,通过整合BSE图像和同视场的定性与定量EDS元素面谱,建立以超像素为基本分析单元的多模态数据集,有效克服孔隙存在及特征X射线与样品相互作用体积过大对物相识别的影响。结合降维和聚类算法,开发可解释的BSE-EDS图像分析模型,实现水泥矿渣复合胶凝体系物相组成的自动化分类。基于Glue平台构建多视图交互分析技术,实现化学元素特征、物相含量分布和离子迁移路径的可视化、同步、联动表征。基于PHATE(Potential of heat-diffusion for affinity-based trajectory embedding)图像构建物相网络拓扑图,通过节点-连接拓扑关系量化物相演化动态特征。最终形成以EDS图像为核心、BSE图像为辅助的智能分析范式,实现化学模态(元素组成、物相类别)与空间模态(孔隙分布、物相分布)的协同定量表征,达成“单次独立微观表征-多模态特征融合分析”的技术愿景,为胶凝体系反应机理研究及微观结构动态演化分析提供较为综合全面的技术支撑。
文摘In this study, the allotropic phase transition and its effect on the magnetic behavior of Fe Co–7 wt%V alloy were investigated. It was found that c phase is observed in the microstructure in the as-cast condition, and it diminishes after severe cold rolling（90% reduction）. After annealing at temperatures higher than 500 up to 750 ℃, the c phase is observed in the structure, again. But, this phase is disappeared by annealing at temperatures above 750 ℃ due to the formation of vanadium-rich precipitates. Thermocalc software was used in order to elucidate the influence of vanadium percent on the stability of c phase in Fe–Co alloys. Also, magnetic studies showed that the saturation induction is reduced by annealing at temperatures from 500 up to 750 ℃, which is related to the formation of residual non-magnetic γ phase.
