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
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
By means of scanning electron microscopy(SEM), energy dispersive spectrum(EDS), X-ray diffractometry(XRD) and metallographic analysis, the effects of variation of magnesium content on phase constituents of Al-Mg-Si-Cu...By means of scanning electron microscopy(SEM), energy dispersive spectrum(EDS), X-ray diffractometry(XRD) and metallographic analysis, the effects of variation of magnesium content on phase constituents of Al-Mg-Si-Cu alloys were investigated. The results indicate that the constituents formed during casting alloys are main Al1.9CuMg4.1Si3.3,Al4(MnFe)3Si2 and Mg2Si, while pure Si is only present in the alloy containing lower magnesium content. Increasing Mg content leads to increasing the amount of Mg2Si, but decreasing the amount of Al1.9CuMg4.1Si3.3 and Al4(MnFe)3Si2. During the following homogenization process, Al1.9CuMg4.1Si3.3 is completely dissolved, Al4(MnFe)3Si2 and pure Si remain unchanged. After rolling and final heat treatment, the constituents in the alloys change no longer.展开更多
The effect of Cr content and cooling rate on the microstructure of Al-Mn alloy was studied using well resistance furnace melting,and the alloy was analyzed using scanning electron microscopy(SEM)and X-ray diffraction(...The effect of Cr content and cooling rate on the microstructure of Al-Mn alloy was studied using well resistance furnace melting,and the alloy was analyzed using scanning electron microscopy(SEM)and X-ray diffraction(XRD).The experimental results showed that adding Cr could significantly improve the morphology of the primary phase in the Al-2.5Mn alloy.Without Cr,the primary phase in the alloy was thick,needle-like,and strip-like structure.After adding 0.2wt%-0.5wt%Cr,the primary phase in the upper part of the alloy was gradually fined and reached the best effect at 0.35wt%Cr.When the content of Cr was 0.5wt%,the microstructure of the primary phase in the upper part began to coarsen.The bottom of the alloy was a large bulk phase,but still much finer than that without adding Cr.XRD and SEM analysis showed that the precipitation phase at the bottom was mainly Al85Mn7Cr8,while the fine microstructure at the top was Al6Mn and Al3Mn.The results of the cooling rate experiments showed that the primary phase of Al-2.5Mn-0.35Cr was further refined,and the eutectic microstructure was partly achieved,under air-cooling condition.And when the cooling method was iron die-cooling,the microstructure of the Al-2.5Mn-0.35Cr alloy was changed into a eutectic microstructure.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
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
The sorption and phase distribution of 20% ethanol and butanol blended gasoline （E20 and B20） vapours have been examined in soils with varying soil organic matter （SOM） and water contents via laboratory microcosm ...The sorption and phase distribution of 20% ethanol and butanol blended gasoline （E20 and B20） vapours have been examined in soils with varying soil organic matter （SOM） and water contents via laboratory microcosm experiments. The presence of 20% alcohol reduced the sorption of gasoline compounds by soil as well as the mass distribution of the compounds to soil solids. This effect was greater for ethanol than butanol. Compared with the sorption coefficient （Kd） of unblended gasoline compounds, the Kd of E20 gasoline compounds decreased by 54% for pentane, 54% for methylcyclopentane （MCP） and 63% for benzene, while the Kd of B20 gasoline compounds decreased by 39% for pentane, 38% for MCP and 49% for benzene, The retardation factor （R） of E20 gasoline compounds decreased by 53% for pentane, 53% for MCP and 48% for benzene, while the R of B20 gasoline compounds decreased by 39% for pentane, 37% for MCP and 38% for benzene. For all SOM and water contents tested, the Kd and R of all gasoline compounds were in the order of unblended gasoline 〉 B20 〉 E20, indicating that the use of high ethanol volume in gasoline to combat climate change could put the groundwater at greater risk of contamination,展开更多
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).
文摘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.
文摘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.
文摘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Project(2002AA331050) supported by Hi-tech Research and Development Program of China project(0208) supported by Science and Technology Research of Ministry of Education of China
文摘By means of scanning electron microscopy(SEM), energy dispersive spectrum(EDS), X-ray diffractometry(XRD) and metallographic analysis, the effects of variation of magnesium content on phase constituents of Al-Mg-Si-Cu alloys were investigated. The results indicate that the constituents formed during casting alloys are main Al1.9CuMg4.1Si3.3,Al4(MnFe)3Si2 and Mg2Si, while pure Si is only present in the alloy containing lower magnesium content. Increasing Mg content leads to increasing the amount of Mg2Si, but decreasing the amount of Al1.9CuMg4.1Si3.3 and Al4(MnFe)3Si2. During the following homogenization process, Al1.9CuMg4.1Si3.3 is completely dissolved, Al4(MnFe)3Si2 and pure Si remain unchanged. After rolling and final heat treatment, the constituents in the alloys change no longer.
基金financially supported by the Research Foundation of Shenyang Aerospace University
文摘The effect of Cr content and cooling rate on the microstructure of Al-Mn alloy was studied using well resistance furnace melting,and the alloy was analyzed using scanning electron microscopy(SEM)and X-ray diffraction(XRD).The experimental results showed that adding Cr could significantly improve the morphology of the primary phase in the Al-2.5Mn alloy.Without Cr,the primary phase in the alloy was thick,needle-like,and strip-like structure.After adding 0.2wt%-0.5wt%Cr,the primary phase in the upper part of the alloy was gradually fined and reached the best effect at 0.35wt%Cr.When the content of Cr was 0.5wt%,the microstructure of the primary phase in the upper part began to coarsen.The bottom of the alloy was a large bulk phase,but still much finer than that without adding Cr.XRD and SEM analysis showed that the precipitation phase at the bottom was mainly Al85Mn7Cr8,while the fine microstructure at the top was Al6Mn and Al3Mn.The results of the cooling rate experiments showed that the primary phase of Al-2.5Mn-0.35Cr was further refined,and the eutectic microstructure was partly achieved,under air-cooling condition.And when the cooling method was iron die-cooling,the microstructure of the Al-2.5Mn-0.35Cr alloy was changed into a eutectic microstructure.
基金Sponsored by National Science and Technology Support Plan of China (2007BAE51B02)
文摘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）.
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)
文摘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.
文摘The sorption and phase distribution of 20% ethanol and butanol blended gasoline （E20 and B20） vapours have been examined in soils with varying soil organic matter （SOM） and water contents via laboratory microcosm experiments. The presence of 20% alcohol reduced the sorption of gasoline compounds by soil as well as the mass distribution of the compounds to soil solids. This effect was greater for ethanol than butanol. Compared with the sorption coefficient （Kd） of unblended gasoline compounds, the Kd of E20 gasoline compounds decreased by 54% for pentane, 54% for methylcyclopentane （MCP） and 63% for benzene, while the Kd of B20 gasoline compounds decreased by 39% for pentane, 38% for MCP and 49% for benzene, The retardation factor （R） of E20 gasoline compounds decreased by 53% for pentane, 53% for MCP and 48% for benzene, while the R of B20 gasoline compounds decreased by 39% for pentane, 37% for MCP and 38% for benzene. For all SOM and water contents tested, the Kd and R of all gasoline compounds were in the order of unblended gasoline 〉 B20 〉 E20, indicating that the use of high ethanol volume in gasoline to combat climate change could put the groundwater at greater risk of contamination,
