High strength Al Zn Mg Cu alloys were produced by spray forming process, and compacted by hot extrusion. The results show that the as deposited billets have fine grained microstructure and low porosity. After heat tre...High strength Al Zn Mg Cu alloys were produced by spray forming process, and compacted by hot extrusion. The results show that the as deposited billets have fine grained microstructure and low porosity. After heat treatment, mechanical properties increase greatly: tensile strength up to 754 MPa, yield strength up to 722 MPa, fracture elongation up to 8%, and elastic modulus up to 72 GPa, respectively. [展开更多
The microstructure and aging behavior of spray formed Al-Zn-Mg-Cu alloys were investigated as a function of alloying element addition. It is revealed that the grains of the as-deposited alloys are refined with increas...The microstructure and aging behavior of spray formed Al-Zn-Mg-Cu alloys were investigated as a function of alloying element addition. It is revealed that the grains of the as-deposited alloys are refined with increasing Zn element, while the function of Ni addition is to reduce grain boundary particles and eutectic in the as-extruded condition. Particles containing Mg and Zn are found to increase with Zn content increasing, while the role of Ni is to reduce both the number and size of these particles. After uniform heat treatment, parts of educts in grain boundary have melted and the grains have not grown up obviously. After heat extrusion, the microstructure becomes denser and there are many precipitated phases in cross-section while there are second phase arranging along extruded direction in longitudinal section. During artificial aging, the increment of Zn content produces not much effect on peak hardness, in addition to an accelerated overage softening. An addition of about 0.13%Ni, however, gives rise to not only improved peak hardness but also an improvement of property stability at the ageing temperature.展开更多
The Tianqiao Pb-Zn ore deposit of Guizhou Province, China, is located in the mid-east of the Sichuan-Yunnan-Guizhou Pb-Zn-Ag multi-metallic mineralization area, which is representative of the Pb-Zn ore de-posits in th...The Tianqiao Pb-Zn ore deposit of Guizhou Province, China, is located in the mid-east of the Sichuan-Yunnan-Guizhou Pb-Zn-Ag multi-metallic mineralization area, which is representative of the Pb-Zn ore de-posits in this area. It consists of three main orebodies, whose Pb+Zn reserves are more than 0.2 million ton. This paper analyzes the sulfur isotopic composition of these orebodies. The data show that the ore minerals (galena, sphalerite, pyrite) in these orebodies are enriched in heavy sulfur, with δ34SV-CDT values varying between 8.35‰ and 14.44‰, i.e. the δ34SV-CDT values of pyrite are between 12.81‰ and 14.44‰, the mean value is 13.40‰; the δ34SV-CDT values of sphalerite are range from 10.87‰ to 14.00‰, the mean value is 12.53‰; the δ34SV-CDT values of galena are range from 8.35‰ to 9.83‰, the mean value is 8.84‰, and they have the feature of δ34Spyrite>δ34Ssphalerite>δ34Sgalena, which indicates the sulfur isotope in ore-forming fluids has attained equilibrium. The δ34S V-CDT values of the deposit are close to those of sulfates from carbonate strata of different ages in the ore-field (15‰), which suggests that the sulfur in the ore-forming fluids should be derived from the thermo-chemical sulfate reduction of sulfates from the sedimentary strata.展开更多
The Mayuan stratabound Pb-Zn deposit in Nanzheng,Shaanxi Province,is located in the northern margin of the Yangtze Plate,in the southern margin of the Beiba Arch.The orebodies are stratiform and hosted in breciated do...The Mayuan stratabound Pb-Zn deposit in Nanzheng,Shaanxi Province,is located in the northern margin of the Yangtze Plate,in the southern margin of the Beiba Arch.The orebodies are stratiform and hosted in breciated dolostone of the Sinian Dengying Formation.The ore minerals are primarily sphalerite and galena,and the gangue minerals comprise of dolomite,quartz,barite,calcite and solid bitumen.Fluid inclusions from ore-stage quartz and calcite have homogenization tempreatures from 98 to 337℃ and salinities from 7.7 wt%to 22.2 wt%（NaCl equiv.）.The vapor phase of the inclusions is mainly composed of CH_4 with minor CO_2 and H_2S.The δD_（fluid） values of fluid inclusions in quartz and calcite display a range from-68‰ to-113‰（SMOW）,and the δ^（18）O_（fluid）values calculated from δ^（18）O_（quartz） and δ^（18）O_（calcite） values range from 4.5‰ to 16.7‰（SMOW）.These data suggest that the ore-forming fluids may have been derived from evaporitic sea water that had reacted with organic matter.The δ^（13）C_（CH4） values of CH_4 in fluid inclusions range from-37.2‰ to-21.0‰（PDB）,suggesting that the CH_4 in the ore-forming fluids was mainly derived from organic matter.This,together with the abundance of solid bitumen in the ores,suggest that organic matter played an important role in mineralization,and that the thermochemical sulfate reduction（TSR） was the main mechanism of sulfide precipitation.The Mayuan Pb-Zn deposit is a carbonate-hosted epigenetic deposit that may be classified as a Mississippi Valley type（MVT） deposit.展开更多
REE abundances in sulfides from the Huize Zn-Pb ore field were determined with the ICPMS after preconcentration. The REE abundances in 26 sulfide samples （including pyrite, galena and sphalerite） are very low, with ...REE abundances in sulfides from the Huize Zn-Pb ore field were determined with the ICPMS after preconcentration. The REE abundances in 26 sulfide samples （including pyrite, galena and sphalerite） are very low, with the ~REE ranging from 1.6×10^-9 to 166.8×10^-9. Their LREE/HREE ratios range from 7.6 to 98, showing LREE enrichment relatively. The JEu values are below 1, indicating that they were deposited from an Eu-depleted and reducing fluid-system. Similar to the ore-hosting carbonate strata, calcite separates from carbonate veinlets filling in the fractures or faults crosscutting the carbonate strata also show clear Eu-depletion. This indicates that the carbonate veinlets and their parent fluid was possibly sourced from the strata and inherited the REE geochemical features of the strata. Therefore, REE-geochemical characteristics of both the sulfides and calcites, which were deposited from an ore-forming hydrothermal system, are similar to those of carbonate strata, and strongly suggest that the ore metals were mainly sourced from carbonate strata.展开更多
The Liaoji Proterozoic rift is an inter-intracontinenatl rift developed from Archean granite-greenstone tectonic regime and contains many important mineral deposits of U, B, magnesite, Pb-Zn, Au, Ag, Co and P. These d...The Liaoji Proterozoic rift is an inter-intracontinenatl rift developed from Archean granite-greenstone tectonic regime and contains many important mineral deposits of U, B, magnesite, Pb-Zn, Au, Ag, Co and P. These deposits were formed as the result of late mobilization, transportation and concentfation of the previously enriched ore-forming mate- rials in several ore-bearing formations formed during the rift stage. So the metallogeny of these deposits in the rift shows both inheritance and new generation of the ore-forming materials. In future ore-searching practice, attentions should be paid on the studies of the ore-bearing formations in the rift, on the multiple stages of metallogeny and and on multiple derivations of the ore-forming materials.展开更多
文摘High strength Al Zn Mg Cu alloys were produced by spray forming process, and compacted by hot extrusion. The results show that the as deposited billets have fine grained microstructure and low porosity. After heat treatment, mechanical properties increase greatly: tensile strength up to 754 MPa, yield strength up to 722 MPa, fracture elongation up to 8%, and elastic modulus up to 72 GPa, respectively. [
基金Project(2001AA332030) supported by the Hi-tech Research and Development Program of China
文摘The microstructure and aging behavior of spray formed Al-Zn-Mg-Cu alloys were investigated as a function of alloying element addition. It is revealed that the grains of the as-deposited alloys are refined with increasing Zn element, while the function of Ni addition is to reduce grain boundary particles and eutectic in the as-extruded condition. Particles containing Mg and Zn are found to increase with Zn content increasing, while the role of Ni is to reduce both the number and size of these particles. After uniform heat treatment, parts of educts in grain boundary have melted and the grains have not grown up obviously. After heat extrusion, the microstructure becomes denser and there are many precipitated phases in cross-section while there are second phase arranging along extruded direction in longitudinal section. During artificial aging, the increment of Zn content produces not much effect on peak hardness, in addition to an accelerated overage softening. An addition of about 0.13%Ni, however, gives rise to not only improved peak hardness but also an improvement of property stability at the ageing temperature.
基金supported by the National Basic Research Program of China (No. 2007CB411402)the National Natural Science Foundation of China (Grant No. 40573036)
文摘The Tianqiao Pb-Zn ore deposit of Guizhou Province, China, is located in the mid-east of the Sichuan-Yunnan-Guizhou Pb-Zn-Ag multi-metallic mineralization area, which is representative of the Pb-Zn ore de-posits in this area. It consists of three main orebodies, whose Pb+Zn reserves are more than 0.2 million ton. This paper analyzes the sulfur isotopic composition of these orebodies. The data show that the ore minerals (galena, sphalerite, pyrite) in these orebodies are enriched in heavy sulfur, with δ34SV-CDT values varying between 8.35‰ and 14.44‰, i.e. the δ34SV-CDT values of pyrite are between 12.81‰ and 14.44‰, the mean value is 13.40‰; the δ34SV-CDT values of sphalerite are range from 10.87‰ to 14.00‰, the mean value is 12.53‰; the δ34SV-CDT values of galena are range from 8.35‰ to 9.83‰, the mean value is 8.84‰, and they have the feature of δ34Spyrite>δ34Ssphalerite>δ34Sgalena, which indicates the sulfur isotope in ore-forming fluids has attained equilibrium. The δ34S V-CDT values of the deposit are close to those of sulfates from carbonate strata of different ages in the ore-field (15‰), which suggests that the sulfur in the ore-forming fluids should be derived from the thermo-chemical sulfate reduction of sulfates from the sedimentary strata.
基金granted by the China State Mineral Resources Investigation Program(Grant No. 1212011121117)the National Natural Science Foudation of China(Grant No.41102050)the Central University Fund(310827153407)
文摘The Mayuan stratabound Pb-Zn deposit in Nanzheng,Shaanxi Province,is located in the northern margin of the Yangtze Plate,in the southern margin of the Beiba Arch.The orebodies are stratiform and hosted in breciated dolostone of the Sinian Dengying Formation.The ore minerals are primarily sphalerite and galena,and the gangue minerals comprise of dolomite,quartz,barite,calcite and solid bitumen.Fluid inclusions from ore-stage quartz and calcite have homogenization tempreatures from 98 to 337℃ and salinities from 7.7 wt%to 22.2 wt%（NaCl equiv.）.The vapor phase of the inclusions is mainly composed of CH_4 with minor CO_2 and H_2S.The δD_（fluid） values of fluid inclusions in quartz and calcite display a range from-68‰ to-113‰（SMOW）,and the δ^（18）O_（fluid）values calculated from δ^（18）O_（quartz） and δ^（18）O_（calcite） values range from 4.5‰ to 16.7‰（SMOW）.These data suggest that the ore-forming fluids may have been derived from evaporitic sea water that had reacted with organic matter.The δ^（13）C_（CH4） values of CH_4 in fluid inclusions range from-37.2‰ to-21.0‰（PDB）,suggesting that the CH_4 in the ore-forming fluids was mainly derived from organic matter.This,together with the abundance of solid bitumen in the ores,suggest that organic matter played an important role in mineralization,and that the thermochemical sulfate reduction（TSR） was the main mechanism of sulfide precipitation.The Mayuan Pb-Zn deposit is a carbonate-hosted epigenetic deposit that may be classified as a Mississippi Valley type（MVT） deposit.
基金This Project is supported by the National Natural Science Foundation （No. 40502011, 40372048 and 40425006）.
文摘REE abundances in sulfides from the Huize Zn-Pb ore field were determined with the ICPMS after preconcentration. The REE abundances in 26 sulfide samples （including pyrite, galena and sphalerite） are very low, with the ~REE ranging from 1.6×10^-9 to 166.8×10^-9. Their LREE/HREE ratios range from 7.6 to 98, showing LREE enrichment relatively. The JEu values are below 1, indicating that they were deposited from an Eu-depleted and reducing fluid-system. Similar to the ore-hosting carbonate strata, calcite separates from carbonate veinlets filling in the fractures or faults crosscutting the carbonate strata also show clear Eu-depletion. This indicates that the carbonate veinlets and their parent fluid was possibly sourced from the strata and inherited the REE geochemical features of the strata. Therefore, REE-geochemical characteristics of both the sulfides and calcites, which were deposited from an ore-forming hydrothermal system, are similar to those of carbonate strata, and strongly suggest that the ore metals were mainly sourced from carbonate strata.
文摘The Liaoji Proterozoic rift is an inter-intracontinenatl rift developed from Archean granite-greenstone tectonic regime and contains many important mineral deposits of U, B, magnesite, Pb-Zn, Au, Ag, Co and P. These deposits were formed as the result of late mobilization, transportation and concentfation of the previously enriched ore-forming mate- rials in several ore-bearing formations formed during the rift stage. So the metallogeny of these deposits in the rift shows both inheritance and new generation of the ore-forming materials. In future ore-searching practice, attentions should be paid on the studies of the ore-bearing formations in the rift, on the multiple stages of metallogeny and and on multiple derivations of the ore-forming materials.
