A mononuclear chiral copper（ll） complex, [Cu（RRchxn）2（C（CN）3）2]＇H20 （RRchxn = （1R, 2R）-diaminocyclohexane） （RRchxnH）, and its deuterated compound, [Cu（RRchxn）2（C（CN）3）z].D20 （RRchxnD）, and their...A mononuclear chiral copper（ll） complex, [Cu（RRchxn）2（C（CN）3）2]＇H20 （RRchxn = （1R, 2R）-diaminocyclohexane） （RRchxnH）, and its deuterated compound, [Cu（RRchxn）2（C（CN）3）z].D20 （RRchxnD）, and their isomers, [Cu（trchxn）2（C（CN）3）2]＇H20 （trchxn = trans-l,2-diaminocyclohexane） （trchxnH） and [Cu（trchxn）2（C（CN）3）2]＇D20 （trchxnD） have been prepared and characterized by means of 1R （infrared）, electronic, and CD （circular dichroism） spectra, magnetic susceptibility, and variable-temperature X-ray crystallography as single crystals or powder. Interestingly, depending on grain size of samples, RRchxnH exhibits the monoclinic form and the orthorhombic form, which are distinguished by systematic absence and powder XRD （X-ray diffraction） patterns clearly. Although single crystals did not exhibit phase transition, powder XRD patterns of RRchxnH and weakly hydrogen bonded RRchxnD emerged low-temperature phase of monoclinic in the orthorhombic patterns only around 200-220 K. However, as a control, powder XRD patterns of both trchxnH and trchxnD did not exhibit such phase transition clearly.展开更多
In low carbon microalloyed steels （C 〈 0.1%）, the content of V, Nb and Ti affects the phases transformation kinetic during cooling in the rolling process. The final microstructure determines the required mechanical...In low carbon microalloyed steels （C 〈 0.1%）, the content of V, Nb and Ti affects the phases transformation kinetic during cooling in the rolling process. The final microstructure determines the required mechanical properties such as high formability, high toughness and adequate strength. For this reason it is relevant to identify and determine the volume fraction of the ferrite, bainite and martensite present in the structure. The microalloying elements： V, Nb and Ti promote carbides precipitation during cooling. The precipitates control the grain size refinement during hot rolling process and the mechanical properties of the steel. In this sense it is necessary to increase the knowledge on the microstructure evolution at different cooling rates. In this paper, the results obtained on two low carbon microalloyed steels （with C contents between 0.11%-0.06%） are reported. An integrated methodology including dilatometry in combination with microscopy techniques was applied. By EBSD （Electron Backscatter Diffraction） technique and microhardness measurements, the structural study was completed. Through a thermodynamic simulation using Fact Sage the type of precipitates in the studied steels structure at the temperature range between 950 ℃ and 450 ℃, were predicted. The information on the evolution of the steel structure at rolling process conditions is relevant to consider changes in processing conditions.展开更多
In this work, commercially pure Zr sheets were subjected to β air cooling and then rolled to different reductions(10% and 50%)at room temperature. Microstructures of both the β-air-cooled and the rolled specimens we...In this work, commercially pure Zr sheets were subjected to β air cooling and then rolled to different reductions(10% and 50%)at room temperature. Microstructures of both the β-air-cooled and the rolled specimens were well characterized by electron channelling contrast imaging and electron backscatter diffraction techniques, with special attentions paid to their misorientation characteristics. Results show that the β-air-cooled specimen owns a Widmanst?tten structure featured by lamellar grains with typical phase transformation misorientations. The 10% rolling allows prismatic slip and tensile twinning({11-21}<11-2-6> and{10-12}<10-11>) to be activated profusely, which produce new low-angle(~3°–5°) and high-angle(~35° and ~85°) misorientation peaks, respectively. After increasing the rolling reduction to 50%, twinning is suppressed and dislocation slip becomes the dominant deformation mode, with the lamellar grains highly elongated and aligned towards the rolling direction.Meanwhile, only one strong low-angle misorientation peak related to the prismatic slip is presented in the 50%-rolled specimen,with all other peaks disappeared. Analyses on local misorientations reveal that hardly any residual strains exist in the β-air-cooled specimen, which should be related to their sufficient relaxation during slow cooling. Residual strains introduced by 10% rolling are heterogeneously distributed near grain/twin boundaries while heavier deformation(50% rolling) produces much larger residual strains pervasively existing throughout the specimen microstructure.展开更多
文摘A mononuclear chiral copper（ll） complex, [Cu（RRchxn）2（C（CN）3）2]＇H20 （RRchxn = （1R, 2R）-diaminocyclohexane） （RRchxnH）, and its deuterated compound, [Cu（RRchxn）2（C（CN）3）z].D20 （RRchxnD）, and their isomers, [Cu（trchxn）2（C（CN）3）2]＇H20 （trchxn = trans-l,2-diaminocyclohexane） （trchxnH） and [Cu（trchxn）2（C（CN）3）2]＇D20 （trchxnD） have been prepared and characterized by means of 1R （infrared）, electronic, and CD （circular dichroism） spectra, magnetic susceptibility, and variable-temperature X-ray crystallography as single crystals or powder. Interestingly, depending on grain size of samples, RRchxnH exhibits the monoclinic form and the orthorhombic form, which are distinguished by systematic absence and powder XRD （X-ray diffraction） patterns clearly. Although single crystals did not exhibit phase transition, powder XRD patterns of RRchxnH and weakly hydrogen bonded RRchxnD emerged low-temperature phase of monoclinic in the orthorhombic patterns only around 200-220 K. However, as a control, powder XRD patterns of both trchxnH and trchxnD did not exhibit such phase transition clearly.
文摘In low carbon microalloyed steels （C 〈 0.1%）, the content of V, Nb and Ti affects the phases transformation kinetic during cooling in the rolling process. The final microstructure determines the required mechanical properties such as high formability, high toughness and adequate strength. For this reason it is relevant to identify and determine the volume fraction of the ferrite, bainite and martensite present in the structure. The microalloying elements： V, Nb and Ti promote carbides precipitation during cooling. The precipitates control the grain size refinement during hot rolling process and the mechanical properties of the steel. In this sense it is necessary to increase the knowledge on the microstructure evolution at different cooling rates. In this paper, the results obtained on two low carbon microalloyed steels （with C contents between 0.11%-0.06%） are reported. An integrated methodology including dilatometry in combination with microscopy techniques was applied. By EBSD （Electron Backscatter Diffraction） technique and microhardness measurements, the structural study was completed. Through a thermodynamic simulation using Fact Sage the type of precipitates in the studied steels structure at the temperature range between 950 ℃ and 450 ℃, were predicted. The information on the evolution of the steel structure at rolling process conditions is relevant to consider changes in processing conditions.
基金supported by the Fundamental and Cutting-Edge Research Plan of Chongqing(Grant Nos.cstc2017jcyj AX0114&cstc2016jcyj A0434)the National Natural Science Foundation of China(Grant Nos.51401040,51601075&51601165)
文摘In this work, commercially pure Zr sheets were subjected to β air cooling and then rolled to different reductions(10% and 50%)at room temperature. Microstructures of both the β-air-cooled and the rolled specimens were well characterized by electron channelling contrast imaging and electron backscatter diffraction techniques, with special attentions paid to their misorientation characteristics. Results show that the β-air-cooled specimen owns a Widmanst?tten structure featured by lamellar grains with typical phase transformation misorientations. The 10% rolling allows prismatic slip and tensile twinning({11-21}<11-2-6> and{10-12}<10-11>) to be activated profusely, which produce new low-angle(~3°–5°) and high-angle(~35° and ~85°) misorientation peaks, respectively. After increasing the rolling reduction to 50%, twinning is suppressed and dislocation slip becomes the dominant deformation mode, with the lamellar grains highly elongated and aligned towards the rolling direction.Meanwhile, only one strong low-angle misorientation peak related to the prismatic slip is presented in the 50%-rolled specimen,with all other peaks disappeared. Analyses on local misorientations reveal that hardly any residual strains exist in the β-air-cooled specimen, which should be related to their sufficient relaxation during slow cooling. Residual strains introduced by 10% rolling are heterogeneously distributed near grain/twin boundaries while heavier deformation(50% rolling) produces much larger residual strains pervasively existing throughout the specimen microstructure.
