P2/O3 composite layered transition metal oxides(LTMOs),constructed by elemental doping,markedly improve sodium storage performance.However,the influence of the doped elements,which usually contribute to electrochemica...P2/O3 composite layered transition metal oxides(LTMOs),constructed by elemental doping,markedly improve sodium storage performance.However,the influence of the doped elements,which usually contribute to electrochemical activity,on the electrochemical performance of the resulting biphasic materials could hardly be ruled out.Herein,three compositionally identical P2/O3-Na0.67Fe0.42Li0.08Mn0.45Sn0.05O2materials are synthesized by calcination at 900℃ for 14,12,and 10 h,yielding P2/O3 ratios of approximately 6:1,3:1,and 2:3,respectively.The resulting materials are designated as PO61,PO31,and PO23,respectively.Cycled at 1 C within the voltage range of 2.0-4.5 V,an initial discharge capacity of 118.3 mAh g-1is delivered by PO31,with a retention rate of 81.1%after 100 cycles,significantly outperforming those of PO61(106.8 mAh g-1,65.0%)and PO23(83.9 mAh g-1,61.5%).Systematic investigation of the charge/discharge behaviour reveals that the mitigated phase transition and enhanced cycling performance in these P2/O3 biphasic materials originate from the formation of shorter Fe-O bonds,which promote structural stabilization.This work provides fundamental insights into phase content regulation and advances the development of LTMOs.展开更多
The phase volume fraction has an important role in the match of the strength and plasticity of dual phase steel.The different bainite contents(18–53 vol.%)in polygonal ferrite and bainite(PF+B)dual phase steel were o...The phase volume fraction has an important role in the match of the strength and plasticity of dual phase steel.The different bainite contents(18–53 vol.%)in polygonal ferrite and bainite(PF+B)dual phase steel were obtained by controlling the relaxation finish temperature during the rolling process.The effect of bainite volume fraction on the tensile deformability was systematically investigated via experiments and crystal plasticity finite element model(CPFEM)simulation.The experimental results showed that the steel showed optimal strain hardenability and strength–plasticity matching when the bainite reached 35%.The 3D-CPFEM models with the same grain size and texture characters were established to clarify the influence of stress/strain distribution on PF+B dual phase steel with different bainite contents.The simulation results indicated that an appropriate increase in the bainite content(18%–35%)did not affect the interphase strain difference,but increased the stress distribution in both phases,as a result of enhancing the coordinated deformability of two phases and improving the strength–plasticity matching.When the bainite content increased to 53%,the stress/strain difference between the two phases was greatly increased,and plastic damage between the two phases was caused by the reduction of the coordinated deformability.展开更多
Bulk YBCO samples were prepared by PMP method. The nominal composition was Y123+xwt% Y211+10 wt% Ag2O (x= 0,15,25,40).The result of magnetic measurements indicated the sample with x= 1 5 at 77 K exhibited a J0 of 3. 9...Bulk YBCO samples were prepared by PMP method. The nominal composition was Y123+xwt% Y211+10 wt% Ag2O (x= 0,15,25,40).The result of magnetic measurements indicated the sample with x= 1 5 at 77 K exhibited a J0 of 3. 9 ×104 A/cm2 at 0.1 T and 2. 4 ×104A/cm2 at 1.0 T.The morphology of samples suggested that fine dispersed Y2BaCuO5 phase acts as effective pinning centers.展开更多
The precipitation characteristics and effect on strengthening mechanism of Cu-rich phases during short-time and long-time aging for Super 304H steels with different Cu content were investigated using X-ray diffraction...The precipitation characteristics and effect on strengthening mechanism of Cu-rich phases during short-time and long-time aging for Super 304H steels with different Cu content were investigated using X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM). The results show that the size of Cu-rich phase particles increases, the interspace of Cu-rich phase particles decreases and the density of Curich phases increases with the increase of Cu content during short-time aging (approximately 800 h) at 650℃ for Super 304H steels. During long-time aging (more than 2 000 h) at 650 ℃, Cu-rich phase precipitates sufficiently and the strengthening effect of Cu-rich phase is preferable in Super 304H steel containing Cu of 4%. The strengthening effect of Cu-rich phase in Super 304H steels containing Cu of 2.2% or 5% is weaker than that with Cu of 4% during long-time aging (more than 2 000 h).展开更多
On the basis of integrated intensity of rocking curves, the multiplicity factor and the diffraction geometry factor for single crystal X-ray diffraction (XRD) analysis were proposed and a general formula for calculati...On the basis of integrated intensity of rocking curves, the multiplicity factor and the diffraction geometry factor for single crystal X-ray diffraction (XRD) analysis were proposed and a general formula for calculating the content of mixed phases was obtained. With a multifunction four-circle X-ray double-crystal diffractometer, pole figures of cubic (002), 1111 and hexagonal 1010 and reciprocal space mapping were measured to investigate the distributive character of mixed phases and to obtain their multiplicity factors and diffraction geometry factors. The contents of cubic twins and hexagonal inclusions were calculated by the integrated intensities of rocking curves of cubic (002), cubic twin 111, hexagonal 1010 and 1011.展开更多
为改善CrNiMo低合金铸钢的综合力学性能,研究了微合金元素钛及淬火温度对其组织与性能的影响规律。通过扫描电子显微镜(scanning electron microscope,SEM)、电子背散射衍射(electron backscatter diffraction,EBSD)、透射电子显微镜(tr...为改善CrNiMo低合金铸钢的综合力学性能,研究了微合金元素钛及淬火温度对其组织与性能的影响规律。通过扫描电子显微镜(scanning electron microscope,SEM)、电子背散射衍射(electron backscatter diffraction,EBSD)、透射电子显微镜(transmission electron microscope,TEM)及光学显微镜(optical microscope,OM)等多种表征方法,分析了钛含量与淬火温度对奥氏体晶粒长大行为的影响,并探讨了钛对回火索氏体形貌及最终力学性能的影响机制。研究结果表明,在900~950℃淬火时,钛含量对奥氏体平均晶粒尺寸影响不显著,但会明显影响晶粒尺寸分布的均匀性。当淬火温度超过1000℃后,钛抑制晶粒粗化的作用更为明显,且淬火温度越高,晶粒尺寸越大。在950℃淬火、钛质量分数为0.035%时,奥氏体晶粒最细小均匀,平均尺寸为11.13μm。机制分析表明,低温淬火时Ti(C,N)未充分溶解,淬火温度主导晶粒尺寸演变。钛含量过低时析出相数量不足,过高则易引起钛原子偏聚,两者均会削弱其对晶界的钉扎效果,影响组织均匀性。经550℃回火后,上述工艺参数对应的试验钢表现出最优的力学性能,抗拉强度为1134.95 MPa,屈服强度为1101.59 MPa,室温冲击功为39.91 J。钛元素通过调控Ti(C,N)析出相的数量与尺寸,在提升钢的强度的同时保持了良好的韧性,实现了强韧性匹配的综合优化。展开更多
Uniaxial tension tests and hole-expansion tests were carried out to determine the influence of silicon on the microstructures, mechanical properties, and stretch-flangeability of conventional dual-phase steels. Compar...Uniaxial tension tests and hole-expansion tests were carried out to determine the influence of silicon on the microstructures, mechanical properties, and stretch-flangeability of conventional dual-phase steels. Compared to 0.03wt% silicon, the addition of 1.08wt% silicon induced the formation of finer ferrite grains (6.8μm ) and a higher carbon content of martensite (Cm≈ 0.32wt%). AS the silicon level increased, the initial strain-hardening rate (n value) and the uniform elongation increased, whereas the yield strength, yield ratio, and stretch-flangeability decreased. The microstructures were observed after hole-expansion tests. The results showed that low carbon content martensite (Cm ≈ 0.19wt%) can easily deform in coordination with ferrite. The relationship between the mechanical properties and stretch-flangeability indicated that the steel with large post-uniform elongation has good stretch-flangeability due to a closer plastic incom- patibility of the ferrite and martensite phases, which can effectively delay the production and decohesion of microvoids.展开更多
基金National Natural Science Foundation of China(22475127,22133005)National Key R&D Program of China(2023YFA1506300)Shanghai Municipal Science and Technology Major Project。
摘要P2/O3 composite layered transition metal oxides(LTMOs),constructed by elemental doping,markedly improve sodium storage performance.However,the influence of the doped elements,which usually contribute to electrochemical activity,on the electrochemical performance of the resulting biphasic materials could hardly be ruled out.Herein,three compositionally identical P2/O3-Na0.67Fe0.42Li0.08Mn0.45Sn0.05O2materials are synthesized by calcination at 900℃ for 14,12,and 10 h,yielding P2/O3 ratios of approximately 6:1,3:1,and 2:3,respectively.The resulting materials are designated as PO61,PO31,and PO23,respectively.Cycled at 1 C within the voltage range of 2.0-4.5 V,an initial discharge capacity of 118.3 mAh g-1is delivered by PO31,with a retention rate of 81.1%after 100 cycles,significantly outperforming those of PO61(106.8 mAh g-1,65.0%)and PO23(83.9 mAh g-1,61.5%).Systematic investigation of the charge/discharge behaviour reveals that the mitigated phase transition and enhanced cycling performance in these P2/O3 biphasic materials originate from the formation of shorter Fe-O bonds,which promote structural stabilization.This work provides fundamental insights into phase content regulation and advances the development of LTMOs.
基金supported by the Project of Liaoning Marine Economic Development(Development of high strength pipeline steel for submarine oil and gas transmission)State Key Laboratory of Metal Material for Marine Equipment and Application Funding(No.SKLMEA-K202205).
摘要The phase volume fraction has an important role in the match of the strength and plasticity of dual phase steel.The different bainite contents(18–53 vol.%)in polygonal ferrite and bainite(PF+B)dual phase steel were obtained by controlling the relaxation finish temperature during the rolling process.The effect of bainite volume fraction on the tensile deformability was systematically investigated via experiments and crystal plasticity finite element model(CPFEM)simulation.The experimental results showed that the steel showed optimal strain hardenability and strength–plasticity matching when the bainite reached 35%.The 3D-CPFEM models with the same grain size and texture characters were established to clarify the influence of stress/strain distribution on PF+B dual phase steel with different bainite contents.The simulation results indicated that an appropriate increase in the bainite content(18%–35%)did not affect the interphase strain difference,but increased the stress distribution in both phases,as a result of enhancing the coordinated deformability of two phases and improving the strength–plasticity matching.When the bainite content increased to 53%,the stress/strain difference between the two phases was greatly increased,and plastic damage between the two phases was caused by the reduction of the coordinated deformability.
摘要Bulk YBCO samples were prepared by PMP method. The nominal composition was Y123+xwt% Y211+10 wt% Ag2O (x= 0,15,25,40).The result of magnetic measurements indicated the sample with x= 1 5 at 77 K exhibited a J0 of 3. 9 ×104 A/cm2 at 0.1 T and 2. 4 ×104A/cm2 at 1.0 T.The morphology of samples suggested that fine dispersed Y2BaCuO5 phase acts as effective pinning centers.
基金Sponsored by National Science and Technology Support Plan of China (2007BAE51B02)
摘要The precipitation characteristics and effect on strengthening mechanism of Cu-rich phases during short-time and long-time aging for Super 304H steels with different Cu content were investigated using X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM). The results show that the size of Cu-rich phase particles increases, the interspace of Cu-rich phase particles decreases and the density of Curich phases increases with the increase of Cu content during short-time aging (approximately 800 h) at 650℃ for Super 304H steels. During long-time aging (more than 2 000 h) at 650 ℃, Cu-rich phase precipitates sufficiently and the strengthening effect of Cu-rich phase is preferable in Super 304H steel containing Cu of 4%. The strengthening effect of Cu-rich phase in Super 304H steels containing Cu of 2.2% or 5% is weaker than that with Cu of 4% during long-time aging (more than 2 000 h).
摘要On the basis of integrated intensity of rocking curves, the multiplicity factor and the diffraction geometry factor for single crystal X-ray diffraction (XRD) analysis were proposed and a general formula for calculating the content of mixed phases was obtained. With a multifunction four-circle X-ray double-crystal diffractometer, pole figures of cubic (002), 1111 and hexagonal 1010 and reciprocal space mapping were measured to investigate the distributive character of mixed phases and to obtain their multiplicity factors and diffraction geometry factors. The contents of cubic twins and hexagonal inclusions were calculated by the integrated intensities of rocking curves of cubic (002), cubic twin 111, hexagonal 1010 and 1011.
基金financially supported by the Fundamental Research Funds for the Central Universities of China (No. FRF-TP-12-046A)the Beijing Higher Education Young Elite Teacher Project (No. YETP0355)
摘要Uniaxial tension tests and hole-expansion tests were carried out to determine the influence of silicon on the microstructures, mechanical properties, and stretch-flangeability of conventional dual-phase steels. Compared to 0.03wt% silicon, the addition of 1.08wt% silicon induced the formation of finer ferrite grains (6.8μm ) and a higher carbon content of martensite (Cm≈ 0.32wt%). AS the silicon level increased, the initial strain-hardening rate (n value) and the uniform elongation increased, whereas the yield strength, yield ratio, and stretch-flangeability decreased. The microstructures were observed after hole-expansion tests. The results showed that low carbon content martensite (Cm ≈ 0.19wt%) can easily deform in coordination with ferrite. The relationship between the mechanical properties and stretch-flangeability indicated that the steel with large post-uniform elongation has good stretch-flangeability due to a closer plastic incom- patibility of the ferrite and martensite phases, which can effectively delay the production and decohesion of microvoids.