Influence of three different rolling routes on mechanical anisotropy and formability of commercially pure titanium sheetwas investigated.Route A and Route B are unidirectional rolling(UR)where the rolling direction is...Influence of three different rolling routes on mechanical anisotropy and formability of commercially pure titanium sheetwas investigated.Route A and Route B are unidirectional rolling(UR)where the rolling direction is along initial rolling direction(RD)and transverse direction(TD),respectively.Route C is cross rolling(CR)where the rolling direction is changed by90°aftereach rolling pass.The microstructure and texture,tensile mechanical properties including strength and elongation,and also theanisotropy of the UR and CR sheets were investigated at room temperature.The XRD results indicate that the texture intensity ofrolled samples gradually weakens from Route A to Route C.Compared with Route A and Route B rolled samples,the Route C rolledsamples show a smaller planar anisotropy.The deep drawing tests reveal that cross rolling can avoid the occurrence of earing.Erichsen tests indicate that rolling routes have an effect on stretch formability of pure titanium sheet.展开更多
Continuous bending (CB) process along rolling direction was performed to improve the formability of AZ31 magnesium alloy sheets. The microstructure and texture evolutions were characterized by optical microscopy (OM) ...Continuous bending (CB) process along rolling direction was performed to improve the formability of AZ31 magnesium alloy sheets. The microstructure and texture evolutions were characterized by optical microscopy (OM) and electronic backscatter diffraction (EBSD). The results reveal that the basal texture intensity of continuously bent and annealed (CBA) sample is drastically weakened. A large number of twins are induced on the concave surface by the 1st pass bending and the density of twins obviously declines during the 2nd pass bending owing to the occurrence of detwinning. Due to the asymmetric tension?compression strain states between the outer and inner regions during V-bending, twinning and detwinning are generated alternatively during the CB process. The Erichsen value is 5.2 mm which increases by 41% compared with that of as-received sample. This obvious improvement of formability can be attributed to the weakened basal texture, which leads to a smaller plastic strain ratio (r-value)together with a larger strain-hardening exponent (n-value).展开更多
A red-emitting phosphor GdNbO4：Eu3＋,Bi3＋ was prepared by a high temperature solid-state reaction technique. The phosphor was characterized by X-ray diffraction （XRD）, particle size analyzer and fluorescence spect...A red-emitting phosphor GdNbO4：Eu3＋,Bi3＋ was prepared by a high temperature solid-state reaction technique. The phosphor was characterized by X-ray diffraction （XRD）, particle size analyzer and fluorescence spectrometer. The single phase of GdNbO4：Eu3＋,Bi3＋ was obtained at 1150~C and the average particle diameter was about 2.30 μm. Excitation and emission spectra reveal that the phosphor can be ef- ficiently excited by ultraviolet （UV） light （394 nm） and emit the strong red light of 612 nm due to the Eu3＋ transition of SD0~TF2. The opti- mum content of Eu3＋ doped in the phosphor GdNbOn：Eu3＋ is 20mo1%. The phosphor Gdo.80NbO4：0.20Eu3＋,0.03Bi3＋ shows much stronger photoluminescence intensity and better chromaticity coordinates （x=0.642, 0.352） than GdNbO4：Eu3＋. It is confirmed that Gdo.80NbO4：0.20Eu3＋,0.03Bi3＋ is a potential candidate for near-UV chip-based white light emitting diodes.展开更多
Mg-6 Al-1 Zn-xFe（x = 0,1,3,5 and 7 wt%）alloys were prepared by powder metallurgy and followed by hot extrusion.Majority of Fe element exists as insoluble particles in the alloys.The as-extruded alloys showed higher ...Mg-6 Al-1 Zn-xFe（x = 0,1,3,5 and 7 wt%）alloys were prepared by powder metallurgy and followed by hot extrusion.Majority of Fe element exists as insoluble particles in the alloys.The as-extruded alloys showed higher degradable rates but less stable mechanical properties than as-annealed alloys.Corrosion rate of all the alloys increased with increasing Fe concentration,reaching 2.4 mL cm-2h-1.0.2% yield strength of all the alloys was higher than 150 MPa.In short,Mg-6 Al-1 Zn-xFe alloys have an attractive combination of corrosion and mechanical properties,which holds a bright future for fracturing balls applications.展开更多
Mg-3Al-lZn alloy sheets have been deformed by continuous bending（CB）to investigate the effects of pro-cessing parameters（bending angle and repetitive passes）on the texture and formability.The samples exhibited a b...Mg-3Al-lZn alloy sheets have been deformed by continuous bending（CB）to investigate the effects of pro-cessing parameters（bending angle and repetitive passes）on the texture and formability.The samples exhibited a bimodal microstructure with abnormal growth grains in the surface region and fine grains distributed in the center after CB process followed by annealing.The texture evolution measured by XRD indicated that the basal poles were rotated from ND toward RD,and the texture intensity decreased with the bending angle decreasing and repetitive passes increasing.Compared with the as-received sample,the yield strength of CBA-120-2 sample significantly decreased from 183 to 112 MPa,and a smaller r-value and a larger n-value were obtained.The formability of CB processed samples in annealing condition was significantly enhanced with the highest of Erichsen value of 5.4 mm,increased by about 135%.The improvement of formability was likely attributed to the weakened and RD-tilt basal texture and coarse grains in the surface part.展开更多
基金Project(CDJZR14130009) supported by the Fundamental Research Funds for the Central Universities,ChinaProject(CSTC2012GGB50003) supported by the Scientific and Technological Program of Chongqing Science and Technology Commission,ChinaProject(CSCT2014FAZKTJCSF50004) supported by the Demonstrative Project of Chongqing Science and Technology Commission,China
文摘Influence of three different rolling routes on mechanical anisotropy and formability of commercially pure titanium sheetwas investigated.Route A and Route B are unidirectional rolling(UR)where the rolling direction is along initial rolling direction(RD)and transverse direction(TD),respectively.Route C is cross rolling(CR)where the rolling direction is changed by90°aftereach rolling pass.The microstructure and texture,tensile mechanical properties including strength and elongation,and also theanisotropy of the UR and CR sheets were investigated at room temperature.The XRD results indicate that the texture intensity ofrolled samples gradually weakens from Route A to Route C.Compared with Route A and Route B rolled samples,the Route C rolledsamples show a smaller planar anisotropy.The deep drawing tests reveal that cross rolling can avoid the occurrence of earing.Erichsen tests indicate that rolling routes have an effect on stretch formability of pure titanium sheet.
基金Project(CDJZR13130081)supported by the Fundamental Research Funds for the Central Universities,ChinaProject(CSCT2014FAZKTJCSF50004)supported by the Chongqing Science and Technology Commission,China
文摘Continuous bending (CB) process along rolling direction was performed to improve the formability of AZ31 magnesium alloy sheets. The microstructure and texture evolutions were characterized by optical microscopy (OM) and electronic backscatter diffraction (EBSD). The results reveal that the basal texture intensity of continuously bent and annealed (CBA) sample is drastically weakened. A large number of twins are induced on the concave surface by the 1st pass bending and the density of twins obviously declines during the 2nd pass bending owing to the occurrence of detwinning. Due to the asymmetric tension?compression strain states between the outer and inner regions during V-bending, twinning and detwinning are generated alternatively during the CB process. The Erichsen value is 5.2 mm which increases by 41% compared with that of as-received sample. This obvious improvement of formability can be attributed to the weakened basal texture, which leads to a smaller plastic strain ratio (r-value)together with a larger strain-hardening exponent (n-value).
基金the National"12th Five-year"Science and Technology Support Program of China(No.2011BAE22B03-3)the Project of Chong qing Scientific and Technological Commission(No.CSTC2010AA4048)
文摘A red-emitting phosphor GdNbO4：Eu3＋,Bi3＋ was prepared by a high temperature solid-state reaction technique. The phosphor was characterized by X-ray diffraction （XRD）, particle size analyzer and fluorescence spectrometer. The single phase of GdNbO4：Eu3＋,Bi3＋ was obtained at 1150~C and the average particle diameter was about 2.30 μm. Excitation and emission spectra reveal that the phosphor can be ef- ficiently excited by ultraviolet （UV） light （394 nm） and emit the strong red light of 612 nm due to the Eu3＋ transition of SD0~TF2. The opti- mum content of Eu3＋ doped in the phosphor GdNbOn：Eu3＋ is 20mo1%. The phosphor Gdo.80NbO4：0.20Eu3＋,0.03Bi3＋ shows much stronger photoluminescence intensity and better chromaticity coordinates （x=0.642, 0.352） than GdNbO4：Eu3＋. It is confirmed that Gdo.80NbO4：0.20Eu3＋,0.03Bi3＋ is a potential candidate for near-UV chip-based white light emitting diodes.
基金supported by project of the National Natural Science Foundation of China (51671041, 51701029 and 51531002)the National Key Research and Development Program of China (2016YFB0301100)+2 种基金the Fundamental Research Funds for the Central Universities (106112016CDJXZ138811 and 2018CDGFCL005)the China Postdoctoral Science Foundation Funded Project (2017M620410 and 2018T110942)the Chongqing Postdoctoral Scientific Research Foundation (Xm2017010)
文摘Mg-6 Al-1 Zn-xFe（x = 0,1,3,5 and 7 wt%）alloys were prepared by powder metallurgy and followed by hot extrusion.Majority of Fe element exists as insoluble particles in the alloys.The as-extruded alloys showed higher degradable rates but less stable mechanical properties than as-annealed alloys.Corrosion rate of all the alloys increased with increasing Fe concentration,reaching 2.4 mL cm-2h-1.0.2% yield strength of all the alloys was higher than 150 MPa.In short,Mg-6 Al-1 Zn-xFe alloys have an attractive combination of corrosion and mechanical properties,which holds a bright future for fracturing balls applications.
基金financially supported by the National Natural Science Foundation of China (Nos. 51671041 and 51531002)the National Key Research and Development Plan (No. 2016YFB0301104)+1 种基金Demonstrative Project of Chongqing Science and Technology Commission (No. CSCT2014FAZKTJCSF50004)Fundamental Research Funds for the Central Universities (No. 106112017CDJPT280001)
文摘Mg-3Al-lZn alloy sheets have been deformed by continuous bending（CB）to investigate the effects of pro-cessing parameters（bending angle and repetitive passes）on the texture and formability.The samples exhibited a bimodal microstructure with abnormal growth grains in the surface region and fine grains distributed in the center after CB process followed by annealing.The texture evolution measured by XRD indicated that the basal poles were rotated from ND toward RD,and the texture intensity decreased with the bending angle decreasing and repetitive passes increasing.Compared with the as-received sample,the yield strength of CBA-120-2 sample significantly decreased from 183 to 112 MPa,and a smaller r-value and a larger n-value were obtained.The formability of CB processed samples in annealing condition was significantly enhanced with the highest of Erichsen value of 5.4 mm,increased by about 135%.The improvement of formability was likely attributed to the weakened and RD-tilt basal texture and coarse grains in the surface part.
