Mg alloys have broad application potential thanks to their low density,degradability,and biocompatibility.However,the inherent conflict between corrosion resistance and mechanical properties poses a significant challe...Mg alloys have broad application potential thanks to their low density,degradability,and biocompatibility.However,the inherent conflict between corrosion resistance and mechanical properties poses a significant challenge that restricts the application of Mg alloys as biomaterials.This study investigated the incorporation of Sm(0 wt%,2 wt%,4 wt%,6 wt%)into the Mg-7Gd-0.5Zr-0.5Zn alloy to enhance its mechanical properties and corrosion resistance.The findings suggest that incorporating the Sm element improves the tensile yield strength(TYS),ultimate tensile strength(UTS)and corrosion resistance despite the sacrifice of elongation.The Mg-7Gd-2Sm-0.5Zr-0.5Zn alloy presents an outstanding balance of corrosion resistance and mechanical properties.The TYS,UTS,and fracture elongation(FE)are175 MPa,265.8 MPa,and 19%,respectively.The corrosion rate is significantly reduced from 4.02 to 2.55 mm/y.With the increment of Sm content,the grains are refined,and the texture is weakened.Sm ele ment is beneficial to the promotion of the precipitation of second phases,forming Sm-containing(Mg,Zn)_(3)RE phase and MgsRE phase.Meanwhile,Sm promotes the co-segregation of elements at grain boundaries and stacking faults,which collectively influence the performance.The impacts of elements co-segregation and second phase on strengthening mechanisms and corrosion mechanisms are discussed in detail.展开更多
Many carbonate-hosted talc mineralization,which are widespread in South China,exclusively developed in Carboniferous dolomitic limestone with many siliceous bands and nodules,and cherts.One of those typical deposits i...Many carbonate-hosted talc mineralization,which are widespread in South China,exclusively developed in Carboniferous dolomitic limestone with many siliceous bands and nodules,and cherts.One of those typical deposits is the Guling talc deposit in Mashan County,central Guangxi province,with a talc reserve of1.51 million tons.Mineral associations in the deposit are sample,mainly including talc and calcite.In this paper,Sm-Nd isotopic system and rare earth elements and yttrium(REE + Y) for the hydrothermal calcite intergrown with talc are used to constrain the age and origin of the talc mineralization.The hydrothermal calcite samples from the deposit display Sm and Nd concentrations ranging from 0.18 to 0.85 and 0.85 to 4.56 ppm,respectively,and variable Sm/Nd ratios of 0.21-0.24.These calcites further yield an Sm-Nd isochron age of 232 ±19 Ma(2a)(MSWD = 0.47) with an concordant initial ^(143)Nd-^(144)Nd ratios of 0.511967 ± 0.000017,which should be interpreted as the mineralization age of the Guling talc deposit.In addition,the calcite samples are enriched in REE with the variable SREE contents ranging from 4.82 to21.50 ppm and display relatively consistent chondritenormalized REE + Y patterns with the LREE enrichment(LREE/HREE=2.00-3.60)and the obvious negative Eu(δEu=0.52-0.68)and Ce(δCe=0.16-0.33)anomalies.The Y/Ho ratios of seven calcites varies from 43.30 to59.34,with a mean value of 49.73.The available mineral associations and REE parameters(i.e.,REE patterns and Y/Ho ratios) of those calcites indicate that the ore-forming fluids of the talc mineralization be probably derived from the meteoric waters,in particular evolved ones in the Karst areas and the ore-forming materials(e.g.,Si and Mg) are likely to be originated from the ore-bearing dolostone in the Yanguan Formation(C_1y) and underlying siliceous rocks in the Liujiang Formation(D_3l).Furthermore,the talc mineralization could take place within a hydrothermal system with relative oxidizing environment and middle temperature,due to the obvious negative Eu and Ce anomalies in the calcites in the Guling deposit.展开更多
基金Project supported by the National Natural Science Foundation of China(52301133,52471117)the China Postdoctoral Science Foundation(2023M730276)the Young Elite Scientists Sponsorship Program by China Association for Science and Technology(YESS20210415)。
文摘Mg alloys have broad application potential thanks to their low density,degradability,and biocompatibility.However,the inherent conflict between corrosion resistance and mechanical properties poses a significant challenge that restricts the application of Mg alloys as biomaterials.This study investigated the incorporation of Sm(0 wt%,2 wt%,4 wt%,6 wt%)into the Mg-7Gd-0.5Zr-0.5Zn alloy to enhance its mechanical properties and corrosion resistance.The findings suggest that incorporating the Sm element improves the tensile yield strength(TYS),ultimate tensile strength(UTS)and corrosion resistance despite the sacrifice of elongation.The Mg-7Gd-2Sm-0.5Zr-0.5Zn alloy presents an outstanding balance of corrosion resistance and mechanical properties.The TYS,UTS,and fracture elongation(FE)are175 MPa,265.8 MPa,and 19%,respectively.The corrosion rate is significantly reduced from 4.02 to 2.55 mm/y.With the increment of Sm content,the grains are refined,and the texture is weakened.Sm ele ment is beneficial to the promotion of the precipitation of second phases,forming Sm-containing(Mg,Zn)_(3)RE phase and MgsRE phase.Meanwhile,Sm promotes the co-segregation of elements at grain boundaries and stacking faults,which collectively influence the performance.The impacts of elements co-segregation and second phase on strengthening mechanisms and corrosion mechanisms are discussed in detail.
基金funded by The 12th Five Year Plan project of State Key Laboratory of Ore-deposit Geochemistry,Chinese Academy of Sciences(SKLODG-ZY125-04)China Natural Science Foundation(41372105)
文摘Many carbonate-hosted talc mineralization,which are widespread in South China,exclusively developed in Carboniferous dolomitic limestone with many siliceous bands and nodules,and cherts.One of those typical deposits is the Guling talc deposit in Mashan County,central Guangxi province,with a talc reserve of1.51 million tons.Mineral associations in the deposit are sample,mainly including talc and calcite.In this paper,Sm-Nd isotopic system and rare earth elements and yttrium(REE + Y) for the hydrothermal calcite intergrown with talc are used to constrain the age and origin of the talc mineralization.The hydrothermal calcite samples from the deposit display Sm and Nd concentrations ranging from 0.18 to 0.85 and 0.85 to 4.56 ppm,respectively,and variable Sm/Nd ratios of 0.21-0.24.These calcites further yield an Sm-Nd isochron age of 232 ±19 Ma(2a)(MSWD = 0.47) with an concordant initial ^(143)Nd-^(144)Nd ratios of 0.511967 ± 0.000017,which should be interpreted as the mineralization age of the Guling talc deposit.In addition,the calcite samples are enriched in REE with the variable SREE contents ranging from 4.82 to21.50 ppm and display relatively consistent chondritenormalized REE + Y patterns with the LREE enrichment(LREE/HREE=2.00-3.60)and the obvious negative Eu(δEu=0.52-0.68)and Ce(δCe=0.16-0.33)anomalies.The Y/Ho ratios of seven calcites varies from 43.30 to59.34,with a mean value of 49.73.The available mineral associations and REE parameters(i.e.,REE patterns and Y/Ho ratios) of those calcites indicate that the ore-forming fluids of the talc mineralization be probably derived from the meteoric waters,in particular evolved ones in the Karst areas and the ore-forming materials(e.g.,Si and Mg) are likely to be originated from the ore-bearing dolostone in the Yanguan Formation(C_1y) and underlying siliceous rocks in the Liujiang Formation(D_3l).Furthermore,the talc mineralization could take place within a hydrothermal system with relative oxidizing environment and middle temperature,due to the obvious negative Eu and Ce anomalies in the calcites in the Guling deposit.
