The microstructure evolution and mechanical properties of Mg–6Zn–0.5Ce–xMn(x=0 and 1 wt.%)wrought magnesium alloys were researched,and the morphologies and role of Mn element in the experimental alloys were analyze...The microstructure evolution and mechanical properties of Mg–6Zn–0.5Ce–xMn(x=0 and 1 wt.%)wrought magnesium alloys were researched,and the morphologies and role of Mn element in the experimental alloys were analyzed.The research shows that all of Mn elements form theα-Mn pure phases,which do not participate in the formation of other phases,such as theτ-phases.The mechanical properties of Mn-containing alloys in as-extruded and aged states are superior to Mn-free alloys.During the hot extrusion process,the dispersed fineα-Mn particle phase hinders the migration of grain boundaries and inhibits dynamic recrystallization,which mainly takes effect of grain refining and dispersion hardening.During the aging treatments,the dispersed fineα-Mn particle phase not only hinders the growth of the solution-treated grains,but also becomes the nucleation cores ofβ1 rod-like precipitate phase,which is conducive to increasing the nucleation rate of the precipitate phase.For the aged alloy,the Mn addition mainly takes effect of grain refining and promoting aging strengthening.展开更多
The effect of manganese(Mn)on the microstructure,tensile and impact properties of SA508Gr.4N steel has been experimentally investigated.The influence of Mn content on the substructure of SA508Gr.4N steel was investiga...The effect of manganese(Mn)on the microstructure,tensile and impact properties of SA508Gr.4N steel has been experimentally investigated.The influence of Mn content on the substructure of SA508Gr.4N steel was investigated using the scanning electron microscope,electron back-scattered diffractometer and transmission electron microscope.It was found that the increased Mn content had a beneficial effect on both strength and toughness.Examination of microstructure revealed smaller size of block and larger number of high-angle grain boundaries with higher Mn content.The change of the ultimate tensile strength and toughness with increasing Mn content was attributed to the increased hardenability,the number of high-angle grain boundaries and the crack propagation path by the block refining.展开更多
In this study,four groups of thin plate samples with a wall thickness of 2.2mm,2.5mm,2.7mm,and 3.0mm are prepared by ultra-high vacuum die casting.The effects of Mn,Mg,and Mn/Mg ratio on the microstructure and mechani...In this study,four groups of thin plate samples with a wall thickness of 2.2mm,2.5mm,2.7mm,and 3.0mm are prepared by ultra-high vacuum die casting.The effects of Mn,Mg,and Mn/Mg ratio on the microstructure and mechanical properties of samples with different wall thicknesses are obtained by different test and analysis methods.The results show that as the content of Mn is 0.4%~0.65%,the content of Mg is 0.17%~0.5%,and the Mn/Mg ratio reaches 1.69~1.90,the tensile strength,yield strength,and elongation of HL-111 alloy with a wall thickness of 2~3mm can reach more than 280MPa,120MPa and 10%respectively,and the mechanical properties of the material are greatly improved.In addition,the tensile strength,yield strength,and elongation of HL-111 alloy after T5 heat treatment at 165℃for 510min reach 302.36 MPa,190.32 MPa,and 8.42%.The precipitated phase of Mg2Si leads to changes in strength and elongation.展开更多
The Callovian-Oxfordian carbonate reservoirs are the most important hydrocarbon reservoir in the Samandepe gas field,Amu Darya basin,Turkmenistan.Based on the analysis of Fe,Mn and Sr trace elements,and carbon,oxygen ...The Callovian-Oxfordian carbonate reservoirs are the most important hydrocarbon reservoir in the Samandepe gas field,Amu Darya basin,Turkmenistan.Based on the analysis of Fe,Mn and Sr trace elements,and carbon,oxygen and strontium isotopes,the genesis and evolutionary characteristics of the carbonate reservoirs were studied,and the conclusions were follows：1） Sustained transgressive-regressive cycles played an important role during Callovian-Oxfordian.The reservoir of reef-bank facies was well developed in the period of transgression,while the regional dense cap rocks developed in the period of regression;2） The 87 Sr/86 Sr ratio measured from rudist shells yields an age of 157.2 Ma according to the global strontium isotope curve;3） As diagenetic intensity increased,δ 13 C changed little,and δ 18 O showed strong negative deviation but was still limited to the range of Late Jurassic seawater.High Fe and Sr contents,and low Mn content,and the evolutionary trend of δ 13 C and δ 18 O all indicate that diagenesis occurred in a relatively confined environment,where the fluids were relatively reducing and contained hot brine.The stage of diagenesis reached is mesodiagenesis,which is very favorable for preservation of primary pores in carbonates;4） Strong dissolution of reef limestones,burial dolomitization and hydrothermal calcite precipitation were all the results of the interaction between the 87 Sr-rich diagenetic fluid and rocks;5） The analysis results of isotopes,fluid inclusions and vitrinite reflectance show that the diagenetic fluid was compaction-released water that originated from the deep,coal-bearing clastic strata.展开更多
Manganese(Mn) deficiencies are common in soils on the Loess Plateau of China. This research provided essential information on improving Mn availability in semiarid soils through agricultural practices. Twelve cropping...Manganese(Mn) deficiencies are common in soils on the Loess Plateau of China. This research provided essential information on improving Mn availability in semiarid soils through agricultural practices. Twelve cropping system and fertilization treatments were designed in a 28-year experiment. The cropping systems included long-term fallow, continuous winter wheat cropping, pea(1 year)-winter wheat(2 years)-millet(1 year) rotation(crop-legume rotation) cropping, and continuous alfalfa cropping. The fertilizer treatments under the cropping systems included no-fertilizer control(CK), application of P fertilizer(P), application of N and P fertilizers(NP), and application of N and P fertilizers and manure(NPM), but the NP treatment was excluded in the continuous alfalfa cropping system. Available Mn and Mn fractions of soil samples(0–20 and 20–40 cm depths) were measured and further analyzed quantitatively using path analyses. Results showed that the crop-legume rotation and continuous alfalfa cropping systems significantly increased available Mn compared with the fallow soil. Compared with the no-fertilizer control, manure application increased available Mn in soil of the continuous wheat cropping system. Across all treatments, the averaged content of mineral-, oxide-, carbonateand organic matter-bound and exchangeable Mn accounted for 42.08%, 38.59%, 10.05%, 4.59%, and 0.09% of the total Mn in soil,respectively. Cropping significantly increased exchangeable Mn in soil and the highest increase was 185.7% in the continuous wheat cropping system at 0–20 cm depth, compared with the fallow soil. Fertilization generally increased exchangeable and carbonate-bound Mn in soil. Carbonate-bound Mn was the main and direct source of available Mn in soil, followed by exchangeable and organic matterbound Mn. These results indicated that crop-legume rotation cropping, continuous alfalfa cropping and application of manure, have the potential to promote Mn availability in soils of rainfed farmlands.展开更多
基金funded by National Natural Science Foundation of China(Project No.51701172)Foundation of China Railway Eryuan Engineering Group Co.Ltd.(Project No.KYY2020035(21-21))+1 种基金Natural Science Foundation of Hunan Province(Project No.2018JJ3504)China Postdoctoral Science Foundation(Project No.2018M632977).
文摘The microstructure evolution and mechanical properties of Mg–6Zn–0.5Ce–xMn(x=0 and 1 wt.%)wrought magnesium alloys were researched,and the morphologies and role of Mn element in the experimental alloys were analyzed.The research shows that all of Mn elements form theα-Mn pure phases,which do not participate in the formation of other phases,such as theτ-phases.The mechanical properties of Mn-containing alloys in as-extruded and aged states are superior to Mn-free alloys.During the hot extrusion process,the dispersed fineα-Mn particle phase hinders the migration of grain boundaries and inhibits dynamic recrystallization,which mainly takes effect of grain refining and dispersion hardening.During the aging treatments,the dispersed fineα-Mn particle phase not only hinders the growth of the solution-treated grains,but also becomes the nucleation cores ofβ1 rod-like precipitate phase,which is conducive to increasing the nucleation rate of the precipitate phase.For the aged alloy,the Mn addition mainly takes effect of grain refining and promoting aging strengthening.
基金This work was supported financially by the National Key Research and Development Program of China(No.2016YFB0300203).
文摘The effect of manganese(Mn)on the microstructure,tensile and impact properties of SA508Gr.4N steel has been experimentally investigated.The influence of Mn content on the substructure of SA508Gr.4N steel was investigated using the scanning electron microscope,electron back-scattered diffractometer and transmission electron microscope.It was found that the increased Mn content had a beneficial effect on both strength and toughness.Examination of microstructure revealed smaller size of block and larger number of high-angle grain boundaries with higher Mn content.The change of the ultimate tensile strength and toughness with increasing Mn content was attributed to the increased hardenability,the number of high-angle grain boundaries and the crack propagation path by the block refining.
文摘In this study,four groups of thin plate samples with a wall thickness of 2.2mm,2.5mm,2.7mm,and 3.0mm are prepared by ultra-high vacuum die casting.The effects of Mn,Mg,and Mn/Mg ratio on the microstructure and mechanical properties of samples with different wall thicknesses are obtained by different test and analysis methods.The results show that as the content of Mn is 0.4%~0.65%,the content of Mg is 0.17%~0.5%,and the Mn/Mg ratio reaches 1.69~1.90,the tensile strength,yield strength,and elongation of HL-111 alloy with a wall thickness of 2~3mm can reach more than 280MPa,120MPa and 10%respectively,and the mechanical properties of the material are greatly improved.In addition,the tensile strength,yield strength,and elongation of HL-111 alloy after T5 heat treatment at 165℃for 510min reach 302.36 MPa,190.32 MPa,and 8.42%.The precipitated phase of Mg2Si leads to changes in strength and elongation.
文摘The Callovian-Oxfordian carbonate reservoirs are the most important hydrocarbon reservoir in the Samandepe gas field,Amu Darya basin,Turkmenistan.Based on the analysis of Fe,Mn and Sr trace elements,and carbon,oxygen and strontium isotopes,the genesis and evolutionary characteristics of the carbonate reservoirs were studied,and the conclusions were follows：1） Sustained transgressive-regressive cycles played an important role during Callovian-Oxfordian.The reservoir of reef-bank facies was well developed in the period of transgression,while the regional dense cap rocks developed in the period of regression;2） The 87 Sr/86 Sr ratio measured from rudist shells yields an age of 157.2 Ma according to the global strontium isotope curve;3） As diagenetic intensity increased,δ 13 C changed little,and δ 18 O showed strong negative deviation but was still limited to the range of Late Jurassic seawater.High Fe and Sr contents,and low Mn content,and the evolutionary trend of δ 13 C and δ 18 O all indicate that diagenesis occurred in a relatively confined environment,where the fluids were relatively reducing and contained hot brine.The stage of diagenesis reached is mesodiagenesis,which is very favorable for preservation of primary pores in carbonates;4） Strong dissolution of reef limestones,burial dolomitization and hydrothermal calcite precipitation were all the results of the interaction between the 87 Sr-rich diagenetic fluid and rocks;5） The analysis results of isotopes,fluid inclusions and vitrinite reflectance show that the diagenetic fluid was compaction-released water that originated from the deep,coal-bearing clastic strata.
基金supported by the National Key Technology R&D Program of China(Nos.2015BAD22B01 and 2011BAD31B01)the Agricultural Comprehensive Development of Land Management and Science and Technology Promotion Project of Ningxia,China(No.NTKJ-2014-01)
文摘Manganese(Mn) deficiencies are common in soils on the Loess Plateau of China. This research provided essential information on improving Mn availability in semiarid soils through agricultural practices. Twelve cropping system and fertilization treatments were designed in a 28-year experiment. The cropping systems included long-term fallow, continuous winter wheat cropping, pea(1 year)-winter wheat(2 years)-millet(1 year) rotation(crop-legume rotation) cropping, and continuous alfalfa cropping. The fertilizer treatments under the cropping systems included no-fertilizer control(CK), application of P fertilizer(P), application of N and P fertilizers(NP), and application of N and P fertilizers and manure(NPM), but the NP treatment was excluded in the continuous alfalfa cropping system. Available Mn and Mn fractions of soil samples(0–20 and 20–40 cm depths) were measured and further analyzed quantitatively using path analyses. Results showed that the crop-legume rotation and continuous alfalfa cropping systems significantly increased available Mn compared with the fallow soil. Compared with the no-fertilizer control, manure application increased available Mn in soil of the continuous wheat cropping system. Across all treatments, the averaged content of mineral-, oxide-, carbonateand organic matter-bound and exchangeable Mn accounted for 42.08%, 38.59%, 10.05%, 4.59%, and 0.09% of the total Mn in soil,respectively. Cropping significantly increased exchangeable Mn in soil and the highest increase was 185.7% in the continuous wheat cropping system at 0–20 cm depth, compared with the fallow soil. Fertilization generally increased exchangeable and carbonate-bound Mn in soil. Carbonate-bound Mn was the main and direct source of available Mn in soil, followed by exchangeable and organic matterbound Mn. These results indicated that crop-legume rotation cropping, continuous alfalfa cropping and application of manure, have the potential to promote Mn availability in soils of rainfed farmlands.
