In this paper, the orange peel defect in the surface range of the st14 steel sheet has been investigated using the electron backscattered diffraction (EBSD) technique. It has been found that the orange peel defect in ...In this paper, the orange peel defect in the surface range of the st14 steel sheet has been investigated using the electron backscattered diffraction (EBSD) technique. It has been found that the orange peel defect in the st14 steel sheet was resulted from the local coarse grains which were produced during hot-rolling due to the critical deformation in dual-phase zone. During deep drawing, the coarse grains with {100}<001> microtexture can slip on the {112}<111> slip system to form bulging and yields orange peel defects, while the coarse grains with {112}<110> orientation do not form the defect as the Schmid factor of {112}<111> slip system in it equals zero.展开更多
The Al-Si-Mg alloy which can be strengthened by heat treatment is widely applied to the key components of aerospace and aeronautics. Iron-rich intermetallic compounds are well known to be strongly influential on mecha...The Al-Si-Mg alloy which can be strengthened by heat treatment is widely applied to the key components of aerospace and aeronautics. Iron-rich intermetallic compounds are well known to be strongly influential on mechanical properties in Al-Si-Mg alloys. But intermetallic compounds in cast Al-Si-Mg alloy intermetallics are often misidentified in previous metallurgical studies. It was described as many different compounds, such as AlFeSi, Al8Fe2Si, Al5（Fe, Mn）3Si2 and so on. For the purpose of solving this problem, the intermetallic compounds in cast Al-Si alloys containing 0.5% Mg were investigated in this study. The iron-rich compounds in Al-Si-Mg casting alloys were characterized by optical microscope（OM）, scanning electron microscope（SEM）, energy dispersive X-ray spectrometer（EDS）, electron backscatter diffraction（EBSD） and X-ray powder diffraction（XRD）. The electron backscatter diffraction patterns were used to assess the crystallographic characteristics of intermetallic compounds. The compound which contains Fe/Mg-rich particles with coarse morphologies was Al8FeMg3Si6 in the alloy by using EBSD. The compound belongs to hexagonal system, space group P6_2m, with the lattice parameter a=0.662 nm, c=0.792 nm. The β-phase is indexed as tetragonal Al3FeSi2, space group I4/mcm, a=0.607 nm and c=0.950 nm. The XRD data indicate that Al8FeMg3Si6 and Al3FeSi2 are present in the microstructure of Al-7Si-Mg alloy, which confirms the identification result of EBSD. The present study identified the iron-rich compound in Al-Si-Mg alloy, which provides a reliable method to identify the intermetallic compounds in short time in Al-Si-Mg alloy. Study results are helpful for identification of complex compounds in alloys.展开更多
With the help of FESEM, high resolution electron backscatter diffraction can investigate the grains/subgrains as small as a few tens of nanometers with a good angular resolution （~0.5°）. Fast development of EBS...With the help of FESEM, high resolution electron backscatter diffraction can investigate the grains/subgrains as small as a few tens of nanometers with a good angular resolution （~0.5°）. Fast development of EBSD speed （up to 1100 patterns per second） contributes that the number of published articles related to EBSD has been increasing sharply year by year. This paper reviews the sample preparation, parameters optimization and analysis of EBSD technique, emphasizing on the investigation of ultrafine grained and nanostructured materials processed by severe plastic deformation （SPD）. Detailed and practical parameters of the electropolishing, silica polishing and ion milling have been summarized. It is shown that ion milling is a real universal and promising polishing method for EBSD preparation of almost all materials. There exists a maximum value of indexed points as a function of step size. The optimum step size depends on the magnification and the board resolution/electronic step size. Grains/subgrains and texture, and grain boundary structure are readily obtained by EBSD. Strain and stored energy may be analyzed by EBSD.展开更多
Mechanical properties and texture evolutions of the as-rolled AZ31 Mg sheets were investigated.The results show that the grains of the sheets are significantly refined after hot rolling.The mechanical properties of th...Mechanical properties and texture evolutions of the as-rolled AZ31 Mg sheets were investigated.The results show that the grains of the sheets are significantly refined after hot rolling.The mechanical properties of the as-rolled samples are enhanced due to the grain size refinement.The intensity of basal texture decreases with the increase of deformation ratio,and double-peak type basal texture is discovered in the intermediate and large strain hot rolling processes.The formation of the texture is ascribed to the activities of prismatic and non-basalslips,which is the same as the 30%rolled and 50%rolled samples.The incline of basal planes exerts an effect on the mechanical anisotropy during tension along rolling direction(RD)and transverse direction(TD)at room temperature.展开更多
The microstructure and crystallographic texture characteristics of an extruded ZK60 Mg alloy subjected to cyclic extrusion and compression(CEC) up to 8 passes at 503 K were investigated.The local crystallographic text...The microstructure and crystallographic texture characteristics of an extruded ZK60 Mg alloy subjected to cyclic extrusion and compression(CEC) up to 8 passes at 503 K were investigated.The local crystallographic texture,grain size and distribution,and grain boundary character distributions were analyzed using high-resolution electron backscatter diffraction(EBSD).The results indicate that the microstructure is refined significantly by the CEC processing and the distributions of grain size tend to be more uniform with increasing CEC pass number.The fraction of low angle grain boundaries(LAGBs) decreases after CEC deformation,and a high fraction of high angle grain boundaries(HAGBs) is revealed after 8 passes of CEC.Moreover,the initial fiber texture becomes random during CEC processing and develops a new texture.展开更多
基金This work was supported by the National Natural Science Foundation of China under grant No.50171040.
文摘In this paper, the orange peel defect in the surface range of the st14 steel sheet has been investigated using the electron backscattered diffraction (EBSD) technique. It has been found that the orange peel defect in the st14 steel sheet was resulted from the local coarse grains which were produced during hot-rolling due to the critical deformation in dual-phase zone. During deep drawing, the coarse grains with {100}<001> microtexture can slip on the {112}<111> slip system to form bulging and yields orange peel defects, while the coarse grains with {112}<110> orientation do not form the defect as the Schmid factor of {112}<111> slip system in it equals zero.
基金supported by National Natural Science Foundation of China (Grant No. 50864002)Guangxi Provincial Natural Science Foundation of China (Grant No. 0991001)
文摘The Al-Si-Mg alloy which can be strengthened by heat treatment is widely applied to the key components of aerospace and aeronautics. Iron-rich intermetallic compounds are well known to be strongly influential on mechanical properties in Al-Si-Mg alloys. But intermetallic compounds in cast Al-Si-Mg alloy intermetallics are often misidentified in previous metallurgical studies. It was described as many different compounds, such as AlFeSi, Al8Fe2Si, Al5（Fe, Mn）3Si2 and so on. For the purpose of solving this problem, the intermetallic compounds in cast Al-Si alloys containing 0.5% Mg were investigated in this study. The iron-rich compounds in Al-Si-Mg casting alloys were characterized by optical microscope（OM）, scanning electron microscope（SEM）, energy dispersive X-ray spectrometer（EDS）, electron backscatter diffraction（EBSD） and X-ray powder diffraction（XRD）. The electron backscatter diffraction patterns were used to assess the crystallographic characteristics of intermetallic compounds. The compound which contains Fe/Mg-rich particles with coarse morphologies was Al8FeMg3Si6 in the alloy by using EBSD. The compound belongs to hexagonal system, space group P6_2m, with the lattice parameter a=0.662 nm, c=0.792 nm. The β-phase is indexed as tetragonal Al3FeSi2, space group I4/mcm, a=0.607 nm and c=0.950 nm. The XRD data indicate that Al8FeMg3Si6 and Al3FeSi2 are present in the microstructure of Al-7Si-Mg alloy, which confirms the identification result of EBSD. The present study identified the iron-rich compound in Al-Si-Mg alloy, which provides a reliable method to identify the intermetallic compounds in short time in Al-Si-Mg alloy. Study results are helpful for identification of complex compounds in alloys.
基金Project(51975167) supported by the National Natural Science Foundation,ChinaProject(2022ZX01A01) supported by the Key R&D Program in Heilongjiang Province,China。
基金Project (192450/I30) supported by the Norwegian Research Council under the Strategic University Program
文摘With the help of FESEM, high resolution electron backscatter diffraction can investigate the grains/subgrains as small as a few tens of nanometers with a good angular resolution （~0.5°）. Fast development of EBSD speed （up to 1100 patterns per second） contributes that the number of published articles related to EBSD has been increasing sharply year by year. This paper reviews the sample preparation, parameters optimization and analysis of EBSD technique, emphasizing on the investigation of ultrafine grained and nanostructured materials processed by severe plastic deformation （SPD）. Detailed and practical parameters of the electropolishing, silica polishing and ion milling have been summarized. It is shown that ion milling is a real universal and promising polishing method for EBSD preparation of almost all materials. There exists a maximum value of indexed points as a function of step size. The optimum step size depends on the magnification and the board resolution/electronic step size. Grains/subgrains and texture, and grain boundary structure are readily obtained by EBSD. Strain and stored energy may be analyzed by EBSD.
文摘Mechanical properties and texture evolutions of the as-rolled AZ31 Mg sheets were investigated.The results show that the grains of the sheets are significantly refined after hot rolling.The mechanical properties of the as-rolled samples are enhanced due to the grain size refinement.The intensity of basal texture decreases with the increase of deformation ratio,and double-peak type basal texture is discovered in the intermediate and large strain hot rolling processes.The formation of the texture is ascribed to the activities of prismatic and non-basalslips,which is the same as the 30%rolled and 50%rolled samples.The incline of basal planes exerts an effect on the mechanical anisotropy during tension along rolling direction(RD)and transverse direction(TD)at room temperature.
基金Projects(50674067,51074106) supported by the National Natural Science Foundation of ChinaProject(09JC1408200) supported by the Science and Technology Commission of Shanghai Municipality,China
文摘The microstructure and crystallographic texture characteristics of an extruded ZK60 Mg alloy subjected to cyclic extrusion and compression(CEC) up to 8 passes at 503 K were investigated.The local crystallographic texture,grain size and distribution,and grain boundary character distributions were analyzed using high-resolution electron backscatter diffraction(EBSD).The results indicate that the microstructure is refined significantly by the CEC processing and the distributions of grain size tend to be more uniform with increasing CEC pass number.The fraction of low angle grain boundaries(LAGBs) decreases after CEC deformation,and a high fraction of high angle grain boundaries(HAGBs) is revealed after 8 passes of CEC.Moreover,the initial fiber texture becomes random during CEC processing and develops a new texture.
