The undesired {111} texture component for the magnetic properties mainly exists in the sheets of electrical steels by the conventional process, whereas the sheets with the non-{111} texture can be obtained by α→γ→...The undesired {111} texture component for the magnetic properties mainly exists in the sheets of electrical steels by the conventional process, whereas the sheets with the non-{111} texture can be obtained by α→γ→α transformation. In this paper, we mainly investigate the opposite relationship between orientation selection and texture memory in the deformed ultra-low carbon steel sheet during →→ transformation annealing. A 0.5 mm thick hot-rolled sheet is directly subjected to transformation. The result shows that the specific transformation textures are not possible to generate in the sheets without deformation. Besides, transformation annealing is conducted on the recrystallized sheets in hydrogen and vacuum, respectively. The near {100} and {110} grains have the growth advantage at the atmosphere/metal interface, and the initial ferrite textures are retained in vacuum. Cold-rolled sheets with different thicknesses are annealed for transformation in vacuum, hydrogen and nitrogen, respectively.The near {100} and {110} textures are still the preferential orientations at the atmosphere/metal interface. When the surface grains have sufficiently large growth advantage, the {111} grains developed by texture memory effect will be annexed. Otherwise, the {111} grains at the center layer of the sheets are hard to be replaced, and they are retained after α→γ→α transformation cycle. The results of deformed sheets annealed with different heating rates in hydrogen show that the growth of initial recrystallization grains has a great effect on variant selection.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
In situ observation of electron backscattering diffraction technique was used to evaluate the orientation relationships between austenite and α′-martensite（α′-M） for high manganese transformation-induced plastic...In situ observation of electron backscattering diffraction technique was used to evaluate the orientation relationships between austenite and α′-martensite（α′-M） for high manganese transformation-induced plasticity steel.It was noted that different from the thermal martensite,which well obeyed K-S relationship with austenite,the orientation relationship between deformation-induced α′-M with austenite changed during deformation,namely K-S and N-W relations coexisted.No clear differences existed between α′-M variants with two kinds of relationships in terms of martensitic orientation,shape and the misorientation between α′-M variants.And this phenomenon happened in almost all austenitic grains with different orientations investigated in this study.An atom displacement mechanism through conjugate complex slips of partial dislocations in the distorted fcc lattice was applied in this article to interpret the coexistence of K-S and N-W relationships.展开更多
The orientation relationships（ORs）between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied s...The orientation relationships（ORs）between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied steels are identified by selected-area electron diffraction（SAED）as either K–S or N–W ORs.Meanwhile,the ORs were also studied based on numerical fitting of electron backscatter diffraction data method suggested by Miyamoto.The simulated K–S and N–W ORs in the low-index directions generally do not well coincide with the experimental pole figure,which may be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures in the high-index directions{123}_（bcc）.A modified method with simplicity based on Miyamoto’s work was proposed.The results indicate that the ORs determined by modified method are similar to those determined by Miyamoto’method,that is,the OR is near K–S OR for the low-carbon Q–P–T steel,and with the increase of carbon content,the OR is closer to N–W OR in medium-carbon Q–P–T steel.展开更多
基金supported by the National Natural Science Foundation of China(Grant No.51271028)
文摘The undesired {111} texture component for the magnetic properties mainly exists in the sheets of electrical steels by the conventional process, whereas the sheets with the non-{111} texture can be obtained by α→γ→α transformation. In this paper, we mainly investigate the opposite relationship between orientation selection and texture memory in the deformed ultra-low carbon steel sheet during →→ transformation annealing. A 0.5 mm thick hot-rolled sheet is directly subjected to transformation. The result shows that the specific transformation textures are not possible to generate in the sheets without deformation. Besides, transformation annealing is conducted on the recrystallized sheets in hydrogen and vacuum, respectively. The near {100} and {110} grains have the growth advantage at the atmosphere/metal interface, and the initial ferrite textures are retained in vacuum. Cold-rolled sheets with different thicknesses are annealed for transformation in vacuum, hydrogen and nitrogen, respectively.The near {100} and {110} textures are still the preferential orientations at the atmosphere/metal interface. When the surface grains have sufficiently large growth advantage, the {111} grains developed by texture memory effect will be annexed. Otherwise, the {111} grains at the center layer of the sheets are hard to be replaced, and they are retained after α→γ→α transformation cycle. The results of deformed sheets annealed with different heating rates in hydrogen show that the growth of initial recrystallization grains has a great effect on variant selection.
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.
基金financially supported by the National Natural Science Foundation of China(No.51271028)
文摘In situ observation of electron backscattering diffraction technique was used to evaluate the orientation relationships between austenite and α′-martensite（α′-M） for high manganese transformation-induced plasticity steel.It was noted that different from the thermal martensite,which well obeyed K-S relationship with austenite,the orientation relationship between deformation-induced α′-M with austenite changed during deformation,namely K-S and N-W relations coexisted.No clear differences existed between α′-M variants with two kinds of relationships in terms of martensitic orientation,shape and the misorientation between α′-M variants.And this phenomenon happened in almost all austenitic grains with different orientations investigated in this study.An atom displacement mechanism through conjugate complex slips of partial dislocations in the distorted fcc lattice was applied in this article to interpret the coexistence of K-S and N-W relationships.
基金financially supported by the National Natural Science Foundation of China (Nos. 51301106 and 51471110)
文摘The orientation relationships（ORs）between the martensite and the retained austenite in low-and medium-carbon steels after quenching–partitioning–tempering process were studied in this work.The ORs in the studied steels are identified by selected-area electron diffraction（SAED）as either K–S or N–W ORs.Meanwhile,the ORs were also studied based on numerical fitting of electron backscatter diffraction data method suggested by Miyamoto.The simulated K–S and N–W ORs in the low-index directions generally do not well coincide with the experimental pole figure,which may be attributed to both the orientation spread from the ideal variant orientations and high symmetry of the low-index directions.However,the simulated results coincide well with experimental pole figures in the high-index directions{123}_（bcc）.A modified method with simplicity based on Miyamoto’s work was proposed.The results indicate that the ORs determined by modified method are similar to those determined by Miyamoto’method,that is,the OR is near K–S OR for the low-carbon Q–P–T steel,and with the increase of carbon content,the OR is closer to N–W OR in medium-carbon Q–P–T steel.
