基于扫描电子显微镜(scanning electron microscope,SEM)图像对土体微观结构特征进行定量分析是一种科学、有效的方法。目前,土体微结构分析一般是对SEM图像进行二值化处理,但是阈值的选择对结果影响较大。文章基于ArcGIS软件在三维空...基于扫描电子显微镜(scanning electron microscope,SEM)图像对土体微观结构特征进行定量分析是一种科学、有效的方法。目前,土体微结构分析一般是对SEM图像进行二值化处理,但是阈值的选择对结果影响较大。文章基于ArcGIS软件在三维空间中分析不同浸水时间下膨胀土的环境扫描电子显微镜(environmental scanning electron microscope,ESEM)图像,定量分析不同浸水时间下土体的孔隙率,根据孔隙率反算不同浸水时间下灰度图像二值化的阈值。通过ArcGIS软件对灰度图像进行二值化,然后提取不同浸水时间下土体的孔隙、单元体,分析不同浸水时间下其微观结构的变化,研究表明:随着浸水时间的增加,孔隙的平均面积由29.57μm2逐渐增加到60.20μm2;单元体的平均面积由129.84μm2逐渐减小到39.93μm2;单元体、孔隙的形状系数在整个浸水周期内先增大再减小;单元体的排列熵由0.987 3逐渐增加到0.998 5,表明单元体的排列越来越无序,即单元体的定向性逐渐变差。展开更多
The recrystallization behavior of cold-drawn 0.12 wt% C steel during annealing at temperatures 600°C and 650°C was investigated. Hardness tests were used to characterize the recrystallization kinetics. The m...The recrystallization behavior of cold-drawn 0.12 wt% C steel during annealing at temperatures 600°C and 650°C was investigated. Hardness tests were used to characterize the recrystallization kinetics. The micrographs of the steel were obtained using optical microscopy (OM) to characterize the grain microstructure of the non-treated and the annealed steel samples. Annihilation of dislocation defects occur within the soaking time of 5 - 10 minutes for all the deformed steel after annealing at 650°C. Specifically at 5 minutes soaking time the grains elongation is still observed indicating that reformation of grains is not taking place but recovery of the deformed grains. At the 10 minutes annealing time, new grains are observed to begin and full recrystallization is achieved at 15 minutes annealing time. At annealing time between 20 - 25 minutes, grains coarsening are observed indicating the onset of grain growth. The hardness of the material reduces with increasing annealing temperature for all the degree of cold drawn deformation. On the basis of the experimentally obtained hardness values, recrystallization increases with increasing degree of cold drawn deformation for the annealed steel. Recovery process was found to prolong in the 20% cold drawn steel as compared to the 55% cold drawn steel. The prolong recovery process is due to reduction in the driving force. Full recrystallization of the annealed steel is achieved at different soaking time depending on the degree of the cold drawn steel.展开更多
文摘基于扫描电子显微镜(scanning electron microscope,SEM)图像对土体微观结构特征进行定量分析是一种科学、有效的方法。目前,土体微结构分析一般是对SEM图像进行二值化处理,但是阈值的选择对结果影响较大。文章基于ArcGIS软件在三维空间中分析不同浸水时间下膨胀土的环境扫描电子显微镜(environmental scanning electron microscope,ESEM)图像,定量分析不同浸水时间下土体的孔隙率,根据孔隙率反算不同浸水时间下灰度图像二值化的阈值。通过ArcGIS软件对灰度图像进行二值化,然后提取不同浸水时间下土体的孔隙、单元体,分析不同浸水时间下其微观结构的变化,研究表明:随着浸水时间的增加,孔隙的平均面积由29.57μm2逐渐增加到60.20μm2;单元体的平均面积由129.84μm2逐渐减小到39.93μm2;单元体、孔隙的形状系数在整个浸水周期内先增大再减小;单元体的排列熵由0.987 3逐渐增加到0.998 5,表明单元体的排列越来越无序,即单元体的定向性逐渐变差。
文摘The recrystallization behavior of cold-drawn 0.12 wt% C steel during annealing at temperatures 600°C and 650°C was investigated. Hardness tests were used to characterize the recrystallization kinetics. The micrographs of the steel were obtained using optical microscopy (OM) to characterize the grain microstructure of the non-treated and the annealed steel samples. Annihilation of dislocation defects occur within the soaking time of 5 - 10 minutes for all the deformed steel after annealing at 650°C. Specifically at 5 minutes soaking time the grains elongation is still observed indicating that reformation of grains is not taking place but recovery of the deformed grains. At the 10 minutes annealing time, new grains are observed to begin and full recrystallization is achieved at 15 minutes annealing time. At annealing time between 20 - 25 minutes, grains coarsening are observed indicating the onset of grain growth. The hardness of the material reduces with increasing annealing temperature for all the degree of cold drawn deformation. On the basis of the experimentally obtained hardness values, recrystallization increases with increasing degree of cold drawn deformation for the annealed steel. Recovery process was found to prolong in the 20% cold drawn steel as compared to the 55% cold drawn steel. The prolong recovery process is due to reduction in the driving force. Full recrystallization of the annealed steel is achieved at different soaking time depending on the degree of the cold drawn steel.
