Anode foil of aluminum electrolytic capacitor,which requires large surface area for high capacitance,were prepared by rolling,annealing and electrochemical etching.Effects of cerium addition on the capacitance of alum...Anode foil of aluminum electrolytic capacitor,which requires large surface area for high capacitance,were prepared by rolling,annealing and electrochemical etching.Effects of cerium addition on the capacitance of aluminum electrolytic capacitors were investigated.Microstructure of the aluminum foil surface was observed by optical microscopy(OM) and scanning electron microscopy(SEM).Electron back scattered diffraction(EBSD) was also employed to reveal texture evolvement of cold-rolled aluminum foil after annealed.The results showed that addition of cerium contributed to higher <100> texture and higher etch pit density as well.Moreover,the distribution of etch tunnels was more uniform compared with that without cerium addition.Perfect specific surface area was obtained with 0.0074% addition of cerium.展开更多
The influence of direct quenching (DQ) on microstructure and mechanical properties of 0.19C-1.7Si-1.0 Mn-0.05Nb steel was studied. The microstructure and mechanical properties of reheat quenched and tempered (RQ&T...The influence of direct quenching (DQ) on microstructure and mechanical properties of 0.19C-1.7Si-1.0 Mn-0.05Nb steel was studied. The microstructure and mechanical properties of reheat quenched and tempered (RQ&T) steel plate were compared with those of direct quenched and tempered (DQ&T) steel plates which were hot rolled at different finish rolling tem-peratures (1173 K and 1123 K), i.e., recrystallization-controlled-rolled direct-quenched (RCR&DQ) and controlled-rolled direct-quenched (CR&DQ), respectively. The strengths generally increased in the following order: RQ&T<RCR&DQ&T< CR&DQ&T. Strength differences between the CR&DQ&T and RQ&T conditions as high as 14% were observed at the tempered temperature of 573 K. The optical microscopy of the CR&DQ&T steel showed deformed grains elongated along the rolling direction, while complete equiaxed grains were visible in RQ&T and RCR&DQ&T steels. Transmission electron microscopy (TEM) and electron backscattering diffraction (EBSD) of the DQ steels showed smaller block width and higher density of dislocations. Inheritance of austenite deformation substructure by the martensite and differences in martensite block width were ruled out as major causes for the strength differences between DQ and RQ steels.展开更多
In order to locate a reasonable heating system,the austenite grain growth behavior of Nb microalloyed medium carbon steel has been experimentally studied at various austenitizing temperatures and for different holding...In order to locate a reasonable heating system,the austenite grain growth behavior of Nb microalloyed medium carbon steel has been experimentally studied at various austenitizing temperatures and for different holding times.It is indicated that austenite grain growth increases with increasing austenitizing temperatures and holding times.Particularly when the austenitizing temperature was above 1100 ℃,austenite grains grew rapidly,and an abnormal austenite grain growth was observed.When the austenitizing temperature was lower than 1100 ℃,austenite grain size and growth rate were small.The activation energy of grain growth in the tested steel is 397 679.5 J/mol.To ensure an absence of coarse grains in microstructures,the heating technology of the tested steel should be controlled for 1 h at 1100 ℃.The relationships of austenite average grain size with soaking temperature and time of tested steel were obtained by mathematical calculation,and austenite average grain size was found to be in agreement with the measured size for different holding times.展开更多
基金supported by the Inner Mongolia Important Science & Technology Project (20071911)Inner Mongolia Technology Research & Development Project
文摘Anode foil of aluminum electrolytic capacitor,which requires large surface area for high capacitance,were prepared by rolling,annealing and electrochemical etching.Effects of cerium addition on the capacitance of aluminum electrolytic capacitors were investigated.Microstructure of the aluminum foil surface was observed by optical microscopy(OM) and scanning electron microscopy(SEM).Electron back scattered diffraction(EBSD) was also employed to reveal texture evolvement of cold-rolled aluminum foil after annealed.The results showed that addition of cerium contributed to higher <100> texture and higher etch pit density as well.Moreover,the distribution of etch tunnels was more uniform compared with that without cerium addition.Perfect specific surface area was obtained with 0.0074% addition of cerium.
文摘The influence of direct quenching (DQ) on microstructure and mechanical properties of 0.19C-1.7Si-1.0 Mn-0.05Nb steel was studied. The microstructure and mechanical properties of reheat quenched and tempered (RQ&T) steel plate were compared with those of direct quenched and tempered (DQ&T) steel plates which were hot rolled at different finish rolling tem-peratures (1173 K and 1123 K), i.e., recrystallization-controlled-rolled direct-quenched (RCR&DQ) and controlled-rolled direct-quenched (CR&DQ), respectively. The strengths generally increased in the following order: RQ&T<RCR&DQ&T< CR&DQ&T. Strength differences between the CR&DQ&T and RQ&T conditions as high as 14% were observed at the tempered temperature of 573 K. The optical microscopy of the CR&DQ&T steel showed deformed grains elongated along the rolling direction, while complete equiaxed grains were visible in RQ&T and RCR&DQ&T steels. Transmission electron microscopy (TEM) and electron backscattering diffraction (EBSD) of the DQ steels showed smaller block width and higher density of dislocations. Inheritance of austenite deformation substructure by the martensite and differences in martensite block width were ruled out as major causes for the strength differences between DQ and RQ steels.
文摘In order to locate a reasonable heating system,the austenite grain growth behavior of Nb microalloyed medium carbon steel has been experimentally studied at various austenitizing temperatures and for different holding times.It is indicated that austenite grain growth increases with increasing austenitizing temperatures and holding times.Particularly when the austenitizing temperature was above 1100 ℃,austenite grains grew rapidly,and an abnormal austenite grain growth was observed.When the austenitizing temperature was lower than 1100 ℃,austenite grain size and growth rate were small.The activation energy of grain growth in the tested steel is 397 679.5 J/mol.To ensure an absence of coarse grains in microstructures,the heating technology of the tested steel should be controlled for 1 h at 1100 ℃.The relationships of austenite average grain size with soaking temperature and time of tested steel were obtained by mathematical calculation,and austenite average grain size was found to be in agreement with the measured size for different holding times.
