Cryogenic rolling experiments have been conducted on the AZ31 magnesium(Mg)alloy sheet with bimodal non-basal texture,which is fabricated via the newly developed equal channel angular rolling and continuous bending pr...Cryogenic rolling experiments have been conducted on the AZ31 magnesium(Mg)alloy sheet with bimodal non-basal texture,which is fabricated via the newly developed equal channel angular rolling and continuous bending process with subsequent annealing(ECAR-CB-A)process.Results demonstrate that this sheet shows no edge cracks until the accumulated thickness reduction reaches about 18.5%,which is about 105.6%larger than that of the sheet with traditional basal texture.Characterization experiments including optical microstructure(OM),X-ray diffractometer(XRD),and electron backscatter diffraction(EBSD)measurements are then performed to explore the microstructure characteristics,texture evolution and deformation mechanisms during cryogenic rolling.Experimental observations confirm the occurrence of abundant{10–12}extension twins(ETs),twin-twin interactions among{10–12}ET variants and{10–12}-{10–12}double twins(DTs).The twinning behaviors as for{10–12}ETs are responsible for the concentration of c-axes of grains towards normal direction(ND)and the formation of transverse direction(TD)-component texture at the beginning of cryogenic rolling.The twinning behaviors with respect to{10–12}-{10–12}DTs are responsible for the disappearance of TD-component texture at the later stage of cryogenic rolling.The involved deformation mechanisms can be summarized as follows:Firstly{10–12}ETs dominate the plastic deformation.Subsequently,dislocation slip,especially basal<a>slip,starts to sustain more plastic strain,while{10–12}ETs occur more frequently and enlarge continuously,resulting in the formation of twin-twin interaction among{10–12}ET variants.With the increasing rolling passes,{10–12}-{10–12}DTs incorporate in the plastic deformation and dislocation slip serves as the major one to sustain plastic strain.The activities of basal<a>slip,{10–12}ETs and{10–12}-{10–12}DTs benefit in accommodating the plastic strain in sheet thickness,which contributes to the improved rolling formability in AZ31 Mg alloy sheet with bimodal non-basal texture during cryogenic rolling.展开更多
The relationship between activities of involved deformation mechanisms and the evolution of microstructure and texture during uniaxial tension of AZ31 magnesium alloy with a rare non-basal texture has been thoroughly ...The relationship between activities of involved deformation mechanisms and the evolution of microstructure and texture during uniaxial tension of AZ31 magnesium alloy with a rare non-basal texture has been thoroughly investigated in the present study by means of electron backscattered diffraction(EBSD) measurement and visco-plastic self-consistent(VPSC) modeling. These results show that except basal slip and prismatic slip, {10■2} extension twin(ET) also plays a significant role during plastic deformation. With the increasing tilted angle between loading direction and rolling direction(RD) of sheet, the activity of {10■2} ET possesses a decreasing tendency and its role in plastic deformation changes from the one mainly sustaining plastic strain to the one mainly accommodating local strain between individual grains. When {10■2} ET serves as a carrier of plastic strain, it mainly results in the formation of basal texture component(c-axis//ND, normal direction). By comparison, when the role of {10■2} ET is to accommodate local strain, it mainly brings about the formation of prismatic texture component(c-axis//TD, transverse direction). At large plastic deformation, the competition between basal slip and pyramidal<c+a> slip is responsible for the concentration of tilted basal poles towards ND within all deformed samples. The larger difference is between the activities of basal slip and pyramidal <c+a> slip, the smaller separation is between these two tilted basal poles. Besides,VPSC modeling overesttmates volume fractions of {10■2} ET in samples with angle of 0 to 30° between loading direction and RD of sheet because interactions between twin variants are not included in VPSC modeling procedure at the present form. In addition, as compatible deformation between individual grains cannot be considered in VPSC modeling, the predicted volume fractions of {10■2} ET in samples with angle of 45 to 90° between loading direction and RD of sheet are smaller than the correspondingly measured results.展开更多
Objective:Triple-negative breast cancer(estrogen receptor-negative,progesterone receptor-negative and Her2-negative) can be classified into two subtypes:basal and non-basal phenotype.And the basal phenotype is associa...Objective:Triple-negative breast cancer(estrogen receptor-negative,progesterone receptor-negative and Her2-negative) can be classified into two subtypes:basal and non-basal phenotype.And the basal phenotype is associated with poor outcome.The purpose of this study was to figure out the differences of clinicopathological characters and related factors of prognosis between these two subtypes.Methods:Immunohistochemical staining was performed for the CK5/6,CK17 basal markers and EGFR on biopsy samples from 40 triple-negative patients and the clinicopathology features of these samples were investigated.Results:Seventy percent of the patients were diagnosed as the basal phenotype.Compared with the non-basal phenotype,the basal phenotype lesions were significantly larger in diameter with a high nuclear grade.In the node-negative group the basal phenotype clearly showed the same clinicopathological differences.There was statistically significant concordance among all three antibodies.Conclusion:Expression of basal markers identifies a biologically and clinically distinct subgroup of TN tumors,justifying the use of basal markers to define the basal or the non-basal phenotype.It is important to help the doctor deciding the therapeutic strategy for patient with triple-negative breast cancer.展开更多
The inconsistencies regarding the fundamental correlation between Gd content and slip(twinning)activities of Mg alloys appeal further investigations.However,the traditional slip dislocations analysis by TEM is time-co...The inconsistencies regarding the fundamental correlation between Gd content and slip(twinning)activities of Mg alloys appeal further investigations.However,the traditional slip dislocations analysis by TEM is time-consuming,and that by SEM/EBSD cannot recognize the partial slip modes.These urge a more efficient and comprehensive approach to easily distinguish all potential slip modes occurred concurrently in alloy matrix.Here we report a modified lattice rotation analysis that can distinguish all slip systems and provide statistical results for slip activities in Mg alloy matrix.Using this method,the high ductility of Mg-Gd alloy ascribed to the enhanced non-basal slips,cross-slip,and postponed twinning activities by Gd addition is quantitatively clarified.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.51805064,51822509)the Qingnian project of science and technology research program of Chongqing Education Commission of China(Grant No.KJQN202101141).
文摘Cryogenic rolling experiments have been conducted on the AZ31 magnesium(Mg)alloy sheet with bimodal non-basal texture,which is fabricated via the newly developed equal channel angular rolling and continuous bending process with subsequent annealing(ECAR-CB-A)process.Results demonstrate that this sheet shows no edge cracks until the accumulated thickness reduction reaches about 18.5%,which is about 105.6%larger than that of the sheet with traditional basal texture.Characterization experiments including optical microstructure(OM),X-ray diffractometer(XRD),and electron backscatter diffraction(EBSD)measurements are then performed to explore the microstructure characteristics,texture evolution and deformation mechanisms during cryogenic rolling.Experimental observations confirm the occurrence of abundant{10–12}extension twins(ETs),twin-twin interactions among{10–12}ET variants and{10–12}-{10–12}double twins(DTs).The twinning behaviors as for{10–12}ETs are responsible for the concentration of c-axes of grains towards normal direction(ND)and the formation of transverse direction(TD)-component texture at the beginning of cryogenic rolling.The twinning behaviors with respect to{10–12}-{10–12}DTs are responsible for the disappearance of TD-component texture at the later stage of cryogenic rolling.The involved deformation mechanisms can be summarized as follows:Firstly{10–12}ETs dominate the plastic deformation.Subsequently,dislocation slip,especially basal<a>slip,starts to sustain more plastic strain,while{10–12}ETs occur more frequently and enlarge continuously,resulting in the formation of twin-twin interaction among{10–12}ET variants.With the increasing rolling passes,{10–12}-{10–12}DTs incorporate in the plastic deformation and dislocation slip serves as the major one to sustain plastic strain.The activities of basal<a>slip,{10–12}ETs and{10–12}-{10–12}DTs benefit in accommodating the plastic strain in sheet thickness,which contributes to the improved rolling formability in AZ31 Mg alloy sheet with bimodal non-basal texture during cryogenic rolling.
基金the National Natural Science Foundation of China(Grant Nos.51805064,51701034,51822509)the Scientific and Technological Research Program of Chongqing Municipal Education Commission(Grant Nos.KJQN201801137)the Basic and Advanced Research Project of CQ CSTC(Grant Nos.cstc2017jcyj AX0062,cstc2018jcyj AX0035)。
文摘The relationship between activities of involved deformation mechanisms and the evolution of microstructure and texture during uniaxial tension of AZ31 magnesium alloy with a rare non-basal texture has been thoroughly investigated in the present study by means of electron backscattered diffraction(EBSD) measurement and visco-plastic self-consistent(VPSC) modeling. These results show that except basal slip and prismatic slip, {10■2} extension twin(ET) also plays a significant role during plastic deformation. With the increasing tilted angle between loading direction and rolling direction(RD) of sheet, the activity of {10■2} ET possesses a decreasing tendency and its role in plastic deformation changes from the one mainly sustaining plastic strain to the one mainly accommodating local strain between individual grains. When {10■2} ET serves as a carrier of plastic strain, it mainly results in the formation of basal texture component(c-axis//ND, normal direction). By comparison, when the role of {10■2} ET is to accommodate local strain, it mainly brings about the formation of prismatic texture component(c-axis//TD, transverse direction). At large plastic deformation, the competition between basal slip and pyramidal<c+a> slip is responsible for the concentration of tilted basal poles towards ND within all deformed samples. The larger difference is between the activities of basal slip and pyramidal <c+a> slip, the smaller separation is between these two tilted basal poles. Besides,VPSC modeling overesttmates volume fractions of {10■2} ET in samples with angle of 0 to 30° between loading direction and RD of sheet because interactions between twin variants are not included in VPSC modeling procedure at the present form. In addition, as compatible deformation between individual grains cannot be considered in VPSC modeling, the predicted volume fractions of {10■2} ET in samples with angle of 45 to 90° between loading direction and RD of sheet are smaller than the correspondingly measured results.
基金Supported by a grant from the National Natural Science Foundation of Hubei Province (No.2009CDB063)
文摘Objective:Triple-negative breast cancer(estrogen receptor-negative,progesterone receptor-negative and Her2-negative) can be classified into two subtypes:basal and non-basal phenotype.And the basal phenotype is associated with poor outcome.The purpose of this study was to figure out the differences of clinicopathological characters and related factors of prognosis between these two subtypes.Methods:Immunohistochemical staining was performed for the CK5/6,CK17 basal markers and EGFR on biopsy samples from 40 triple-negative patients and the clinicopathology features of these samples were investigated.Results:Seventy percent of the patients were diagnosed as the basal phenotype.Compared with the non-basal phenotype,the basal phenotype lesions were significantly larger in diameter with a high nuclear grade.In the node-negative group the basal phenotype clearly showed the same clinicopathological differences.There was statistically significant concordance among all three antibodies.Conclusion:Expression of basal markers identifies a biologically and clinically distinct subgroup of TN tumors,justifying the use of basal markers to define the basal or the non-basal phenotype.It is important to help the doctor deciding the therapeutic strategy for patient with triple-negative breast cancer.
基金supported by the grant from the Natural Science Foundation of China(51871244)the Hunan Provincial Innovation Foundation for Postgraduate(CX20200172)the Fundamental Research Funds for the Central Universities of Central South University(1053320190103)
文摘The inconsistencies regarding the fundamental correlation between Gd content and slip(twinning)activities of Mg alloys appeal further investigations.However,the traditional slip dislocations analysis by TEM is time-consuming,and that by SEM/EBSD cannot recognize the partial slip modes.These urge a more efficient and comprehensive approach to easily distinguish all potential slip modes occurred concurrently in alloy matrix.Here we report a modified lattice rotation analysis that can distinguish all slip systems and provide statistical results for slip activities in Mg alloy matrix.Using this method,the high ductility of Mg-Gd alloy ascribed to the enhanced non-basal slips,cross-slip,and postponed twinning activities by Gd addition is quantitatively clarified.
