Biodegradable magnesium alloys show promising potential for pancreatic duct stents,yet their degradation varies significantly across physiological environments.This study compared the corrosion rates of extruded Mg-2Z...Biodegradable magnesium alloys show promising potential for pancreatic duct stents,yet their degradation varies significantly across physiological environments.This study compared the corrosion rates of extruded Mg-2Zn-xMn(x=0,0.5,1.0,1.5 wt.%)alloys in human pancreatic fluid.The results revealed that the alloys undergo different corrosion mechanisms in human pancreatic fluid,emphasizing the necessity of conducting evaluations under physiologically relevant conditions.Further investigations into the degradation mechanism in pancreatic fluid indicated that the alkaline PH(8.3–8.7),high bicarbonate concentration,and enzymatic activity significantly influence the corrosion process.Electrochemical and immersion tests showed rapid initial corrosion due to Cl^(−)attack,followed by the formation of a protective Mg(OH)_(2),MgCO_(3),and Ca_(3)(PO_(4))_(2)layer that slowed degradation.However,digestive enzymes,particularly trypsin,disrupt passivation by interacting with organic components,leading to pitting and filiform corrosion.Among the investigated alloys,Mg-2Zn-1.0Mn exhibited the most favorable combination of corrosion resistance,mechanical performance,and cytocompatibility.This study highlights the critical impact of pancreatic fluid on magnesium alloy degradation and stresses the need for physiologically accurate evaluations.展开更多
The synergistic effect of low Gd+Mn additions on the evolution of microstructure and mechanical properties of Mg−xGd−0.8Mn alloy was investigated.Gd addition shows a strong grain refinement effect on the extruded Mg−x...The synergistic effect of low Gd+Mn additions on the evolution of microstructure and mechanical properties of Mg−xGd−0.8Mn alloy was investigated.Gd addition shows a strong grain refinement effect on the extruded Mg−xGd−0.8Mn alloy,and leads to a continuous decrease in the area fraction of basal texture grains and the corresponding maximum density of texture components.However,the maximum density of the basal texture components grows abruptly as Gd content increases to 6 wt.%.When the Gd content is below 6 wt.%,the asymmetry of the tensile and compressive yield of the alloy is negatively correlated to the Gd content due to grain refinement and texture weakening effects.Besides,the contribution of grain refinement to higher alloy yield strength is more significant than that of grain orientation.Compared with the extruded Mg−xGd alloy,the extruded Mg−xGd−0.8Mn alloy shows a lower limit composition point that corresponds to solid solution strengthening and plasticizing effect(2 wt.%and 4 wt.%).Finally,the trend of basal slip and prismatic slip resistance variations of the extruded Mg−xGd−0.8Mn alloys was predicted.展开更多
Designing and developing the Mg alloys with low cost and high performance is of the great significance.Novel Mg-1Bi-xMn(x=0,1and 2 wt.%)extruded alloys,in this work,were fabricated at different extrusion temperatures(...Designing and developing the Mg alloys with low cost and high performance is of the great significance.Novel Mg-1Bi-xMn(x=0,1and 2 wt.%)extruded alloys,in this work,were fabricated at different extrusion temperatures(220,250 and 300℃).The effects of extrusion temperature and Mn addition on the microstructures and mechanical properties of extruded alloys at room temperature were investigated.The results showed that decreasing the extrusion temperature could refine the average grain size,weaken the basal fiber texture intensity and improve the microstructural homogeneity of extruded alloys.When the Mn element was added to the Mg-1Bi alloy,the average grain size further reduced.Simultaneously,the number fraction of low angle grain boundaries(LAGBs)increased,along with the occurrence of regions without dynamic recrystallization(unDRX).The combined effects of grain refinement and coarse unDRXed structure made the textures of the extruded Mg-1Bi-xMn alloys never obviously change.Besides few large size un-dissolved second phases,fine Mg_(3)Bi_(2) and α-Mn phases were precipitated in the extruded Mg-1Bi-xMn alloys and partial nano-scaleα-Mn particles pined at grain boundaries(GBs)to effectively impede the migration of GBs for grain refinement.Microstructural variations determined the extruded Mg-1Bi-2Mn alloy to exhibit the highest yield strength of~319.2 MPa with the appropriate elongation-to-failure of~13%at the extrusion temperature of 220℃,and they enabled the extruded Mg-1Bi-1Mn alloy to show the highest elongation-to-failure of~26%without the obvious loss of yield strength of~252.1 MPa.展开更多
The self-corrosion, electrochemical and discharge behavior of commercial purity Al anode via Mn modification in Al-air battery was studied by the hydrogen evolution, weight loss, electrical conductivity, electrochemic...The self-corrosion, electrochemical and discharge behavior of commercial purity Al anode via Mn modification in Al-air battery was studied by the hydrogen evolution, weight loss, electrical conductivity, electrochemical and discharge tests. Results show that the synergetic effects of the dissolved Mn and Mn-modifying Al_(3)Fe intermetallic decrease the weight loss and inhibit the hydrogen evolution of commercial purity Al in Na OH solution when minor Mn is introduced. However, more Mn addition leads to the formation of Al_6Mn intermetallic,which has little effect on the weight loss, but accelerates the hydrogen evolution. Mn introduction plays a positive role in activating Al anodes, resulting in a decrease in the anodic polarization and an increase in the discharge voltage. Among all the commercial purity Al-x Mn anodes, 0.1 wt% Mn addition exhibits the best discharge efficiency for Al-air battery.展开更多
The influence of Mn content on the microstructure,tensile properties and strain-hardening behaviors of extruded Mg−1Gd−0.5Zn−xMn(x=0,0.3 and 1,wt.%)alloy sheets was investigated by X-ray diffraction(XRD),scanning elec...The influence of Mn content on the microstructure,tensile properties and strain-hardening behaviors of extruded Mg−1Gd−0.5Zn−xMn(x=0,0.3 and 1,wt.%)alloy sheets was investigated by X-ray diffraction(XRD),scanning electron microscope(SEM),and electron backscatter diffraction(EBSD).The results show that the completely recrystallized grain structure and the extrusion direction(ED)-titling texture are observed in all the extruded sheets.The mean grain size and weakened ED-titling texture of the extruded sheets are gradually reduced with increasing Mn content.This is primarily associated with the formation of new fineα-Mn particles by Mn addition.Tensile properties show that the addition of Mn also leads to the improvement of yield strengths,ultimate tensile strengths and elongations of the extruded Mg−1Gd−0.5Zn−xMn sheets,which is mainly due to the fine grains andα-Mn particles.In addition,the Mg−1Gd−0.5Zn−1Mn sheet has the lowest strain-hardening exponent and the best hardening capacity among all prepared Mg−1Gd−0.5Zn−xMn sheets.展开更多
The high corrosion sensitivity and the potential bio-toxicity of Mg-Ag alloys limit their wide applications for the production of implanted devices. In the present work, Mn is added into the Mg-Ag alloy to optimize it...The high corrosion sensitivity and the potential bio-toxicity of Mg-Ag alloys limit their wide applications for the production of implanted devices. In the present work, Mn is added into the Mg-Ag alloy to optimize its corrosion behaviour. The corrosion behaviour of Mg-Ag-Mn alloys is investigated with the underlying microstructural factors examined. The Mg-Ag alloy with 2 wt% Mn exhibits the highest corrosion resistance after post-casting heat treatment at 440 ℃. The addition of Mn results in α-Mn phase with the incorporation of Fe, which suppresses the cathodic activity of impurity Fe. Further, heat treatment of the cast alloys homogenizes the distribution of Ag and promotes the precipitation of α-Mn phase. The former removes Ag segregations as potential cathodes;the latter promotes a more uniform distribution of cathodes and, therefore, prevents localized corrosion.展开更多
This work studied the effects of adding Zr and Mn in amounts less than 1wt%on the microstructure,mechanical properties,casting properties,and corrosion resistance of Mg-Zn-Cu alloys containing 2.5wt%Cu and 2.5wt%-6.5w...This work studied the effects of adding Zr and Mn in amounts less than 1wt%on the microstructure,mechanical properties,casting properties,and corrosion resistance of Mg-Zn-Cu alloys containing 2.5wt%Cu and 2.5wt%-6.5wt%Zn.The hardness and electrical conductivity measurements were used to find an optimal heat treatment schedule with the best mechanical properties.It has been established that Zr significantly increases the yield strength of the alloys due to a strong grain refinement effect.However,the presence of Mn and Zr has a detrimental effect on alloy’s elongation at fracture.It was shown that the precipitation of the Mg_(2)Cu cathodic phase in the alloy structure negatively affects the corrosion behavior.Nevertheless,the addition of Mn decreases the corrosion rate of the investigated alloys.The best combination of the mechanical,casting,and corrosion properties were achieved in the alloys containing 2.5wt%Cu and 5wt%Zn.However,the Mn or Zr addition can improve the properties of the alloys;for example,the addition of Mn or Zr increases the fluidity of the alloys.展开更多
基金supported by China National Natural Science Foundation of China(52225101)Graduate Research and Innovation Foundation of Chongqing(CYB240017)+1 种基金National Natural Science Foundation of China(82373128)Natural Science Foundation of Chongqing,China(2024MSXM174)for Shixiang Guo.
文摘Biodegradable magnesium alloys show promising potential for pancreatic duct stents,yet their degradation varies significantly across physiological environments.This study compared the corrosion rates of extruded Mg-2Zn-xMn(x=0,0.5,1.0,1.5 wt.%)alloys in human pancreatic fluid.The results revealed that the alloys undergo different corrosion mechanisms in human pancreatic fluid,emphasizing the necessity of conducting evaluations under physiologically relevant conditions.Further investigations into the degradation mechanism in pancreatic fluid indicated that the alkaline PH(8.3–8.7),high bicarbonate concentration,and enzymatic activity significantly influence the corrosion process.Electrochemical and immersion tests showed rapid initial corrosion due to Cl^(−)attack,followed by the formation of a protective Mg(OH)_(2),MgCO_(3),and Ca_(3)(PO_(4))_(2)layer that slowed degradation.However,digestive enzymes,particularly trypsin,disrupt passivation by interacting with organic components,leading to pitting and filiform corrosion.Among the investigated alloys,Mg-2Zn-1.0Mn exhibited the most favorable combination of corrosion resistance,mechanical performance,and cytocompatibility.This study highlights the critical impact of pancreatic fluid on magnesium alloy degradation and stresses the need for physiologically accurate evaluations.
基金National Natural Science Foundation of China(No.U2241231)National Key Research and Development Program of China(No.2021YFB3701100)+1 种基金Scientific Research Project of Jiangxi Provincial Department of Education,China(No.GJJ211038)Doctoral Research Project of Jinggangshan University,China(No.JZB2110)。
文摘The synergistic effect of low Gd+Mn additions on the evolution of microstructure and mechanical properties of Mg−xGd−0.8Mn alloy was investigated.Gd addition shows a strong grain refinement effect on the extruded Mg−xGd−0.8Mn alloy,and leads to a continuous decrease in the area fraction of basal texture grains and the corresponding maximum density of texture components.However,the maximum density of the basal texture components grows abruptly as Gd content increases to 6 wt.%.When the Gd content is below 6 wt.%,the asymmetry of the tensile and compressive yield of the alloy is negatively correlated to the Gd content due to grain refinement and texture weakening effects.Besides,the contribution of grain refinement to higher alloy yield strength is more significant than that of grain orientation.Compared with the extruded Mg−xGd alloy,the extruded Mg−xGd−0.8Mn alloy shows a lower limit composition point that corresponds to solid solution strengthening and plasticizing effect(2 wt.%and 4 wt.%).Finally,the trend of basal slip and prismatic slip resistance variations of the extruded Mg−xGd−0.8Mn alloys was predicted.
基金financial support from the National Key Research and Development Program of China(U1764253)the Chongqing Scientific&Technological Talents Program(KJXX2017002)。
文摘Designing and developing the Mg alloys with low cost and high performance is of the great significance.Novel Mg-1Bi-xMn(x=0,1and 2 wt.%)extruded alloys,in this work,were fabricated at different extrusion temperatures(220,250 and 300℃).The effects of extrusion temperature and Mn addition on the microstructures and mechanical properties of extruded alloys at room temperature were investigated.The results showed that decreasing the extrusion temperature could refine the average grain size,weaken the basal fiber texture intensity and improve the microstructural homogeneity of extruded alloys.When the Mn element was added to the Mg-1Bi alloy,the average grain size further reduced.Simultaneously,the number fraction of low angle grain boundaries(LAGBs)increased,along with the occurrence of regions without dynamic recrystallization(unDRX).The combined effects of grain refinement and coarse unDRXed structure made the textures of the extruded Mg-1Bi-xMn alloys never obviously change.Besides few large size un-dissolved second phases,fine Mg_(3)Bi_(2) and α-Mn phases were precipitated in the extruded Mg-1Bi-xMn alloys and partial nano-scaleα-Mn particles pined at grain boundaries(GBs)to effectively impede the migration of GBs for grain refinement.Microstructural variations determined the extruded Mg-1Bi-2Mn alloy to exhibit the highest yield strength of~319.2 MPa with the appropriate elongation-to-failure of~13%at the extrusion temperature of 220℃,and they enabled the extruded Mg-1Bi-1Mn alloy to show the highest elongation-to-failure of~26%without the obvious loss of yield strength of~252.1 MPa.
基金financially supported by Anhui Provincial Natural Science Foundation (No. 1808085ME123)the Projects of International Cooperation and Exchanges in Anhui Provincial Key Project of Research and Development Plan (No.1804b06020363)the Priority Funding Scheme for Innovative Projects for Overseas Chinese Students in Anhui Province。
文摘The self-corrosion, electrochemical and discharge behavior of commercial purity Al anode via Mn modification in Al-air battery was studied by the hydrogen evolution, weight loss, electrical conductivity, electrochemical and discharge tests. Results show that the synergetic effects of the dissolved Mn and Mn-modifying Al_(3)Fe intermetallic decrease the weight loss and inhibit the hydrogen evolution of commercial purity Al in Na OH solution when minor Mn is introduced. However, more Mn addition leads to the formation of Al_6Mn intermetallic,which has little effect on the weight loss, but accelerates the hydrogen evolution. Mn introduction plays a positive role in activating Al anodes, resulting in a decrease in the anodic polarization and an increase in the discharge voltage. Among all the commercial purity Al-x Mn anodes, 0.1 wt% Mn addition exhibits the best discharge efficiency for Al-air battery.
基金the National Natural Science Foundation of China(Nos.U1764253,U2037601,52001037 and 51971044)the National Defense Basic Scientific Research Program of China+1 种基金the Chongqing Science and Technology Commission,China(No.cstc2017zdcyzdzx X0006)the Qinghai Science and Technology Program,China(No.2018-GX-A1)。
文摘The influence of Mn content on the microstructure,tensile properties and strain-hardening behaviors of extruded Mg−1Gd−0.5Zn−xMn(x=0,0.3 and 1,wt.%)alloy sheets was investigated by X-ray diffraction(XRD),scanning electron microscope(SEM),and electron backscatter diffraction(EBSD).The results show that the completely recrystallized grain structure and the extrusion direction(ED)-titling texture are observed in all the extruded sheets.The mean grain size and weakened ED-titling texture of the extruded sheets are gradually reduced with increasing Mn content.This is primarily associated with the formation of new fineα-Mn particles by Mn addition.Tensile properties show that the addition of Mn also leads to the improvement of yield strengths,ultimate tensile strengths and elongations of the extruded Mg−1Gd−0.5Zn−xMn sheets,which is mainly due to the fine grains andα-Mn particles.In addition,the Mg−1Gd−0.5Zn−1Mn sheet has the lowest strain-hardening exponent and the best hardening capacity among all prepared Mg−1Gd−0.5Zn−xMn sheets.
基金supported by the National Natural Science Foundation of China(Nos.52001128 and 52371065)the Hubei Provincial Natural Science Foundation of China(No.2023AFB637).
文摘The high corrosion sensitivity and the potential bio-toxicity of Mg-Ag alloys limit their wide applications for the production of implanted devices. In the present work, Mn is added into the Mg-Ag alloy to optimize its corrosion behaviour. The corrosion behaviour of Mg-Ag-Mn alloys is investigated with the underlying microstructural factors examined. The Mg-Ag alloy with 2 wt% Mn exhibits the highest corrosion resistance after post-casting heat treatment at 440 ℃. The addition of Mn results in α-Mn phase with the incorporation of Fe, which suppresses the cathodic activity of impurity Fe. Further, heat treatment of the cast alloys homogenizes the distribution of Ag and promotes the precipitation of α-Mn phase. The former removes Ag segregations as potential cathodes;the latter promotes a more uniform distribution of cathodes and, therefore, prevents localized corrosion.
基金financial support form the Ministry of Science and Higher Education of the Russian Federation in the framework of MegaGrant(No.220-7868-7477)。
文摘This work studied the effects of adding Zr and Mn in amounts less than 1wt%on the microstructure,mechanical properties,casting properties,and corrosion resistance of Mg-Zn-Cu alloys containing 2.5wt%Cu and 2.5wt%-6.5wt%Zn.The hardness and electrical conductivity measurements were used to find an optimal heat treatment schedule with the best mechanical properties.It has been established that Zr significantly increases the yield strength of the alloys due to a strong grain refinement effect.However,the presence of Mn and Zr has a detrimental effect on alloy’s elongation at fracture.It was shown that the precipitation of the Mg_(2)Cu cathodic phase in the alloy structure negatively affects the corrosion behavior.Nevertheless,the addition of Mn decreases the corrosion rate of the investigated alloys.The best combination of the mechanical,casting,and corrosion properties were achieved in the alloys containing 2.5wt%Cu and 5wt%Zn.However,the Mn or Zr addition can improve the properties of the alloys;for example,the addition of Mn or Zr increases the fluidity of the alloys.
