Non-precious metal cobalt-based oxide inevitably dissolves for acid oxygen evolution reaction(OER).Designing an efficient deposition channel for leaching cobalt species is a promising approach.The dissolution-depositi...Non-precious metal cobalt-based oxide inevitably dissolves for acid oxygen evolution reaction(OER).Designing an efficient deposition channel for leaching cobalt species is a promising approach.The dissolution-deposition equilibrium of Co is achieved by doping Mn in the lattice of LaCo_(1-x)Mn_(x)O_(3),prolonging the lifespan in acidic conditions by 14 times.The lattice doping of Mn produces a strain that enhances the adsorption capacity of OH^(-).The self-catalysis of Mn causes the leaching Co to be deposited in the form of CoO_(2),which ensures that the long-term stability of LaCo_(1-x)Mn_(x)O_(3)is 70 h instead of 5 h for LaCoO_(3).Mn doping enhances the deprotonation of^(*)OOH→O_(2)in acidic environments.Notably,the over-potential of optimized LaCo_(1-x)Mn_(x)O_(3)is 345 mV at 10 mA cm^(-2)for acidic OER.This work presents a promising method for developing noble metal-free catalysts that enhance the acidic OER activity and stability.展开更多
1.Introduction.Ni-Mn-X(X=Ga,In,Sn,or Sb)Heusler alloys have versatile properties[1-4],such as shape memory effect[1],superelastic-ity[5],magnetocaloric effect[3],elastocaloric effect[6],and even multicaloric effect[7]...1.Introduction.Ni-Mn-X(X=Ga,In,Sn,or Sb)Heusler alloys have versatile properties[1-4],such as shape memory effect[1],superelastic-ity[5],magnetocaloric effect[3],elastocaloric effect[6],and even multicaloric effect[7],that indicate their potential for use in actu-ators,sensors,micropumps,energy harvesters,and solid-state re-frigeration[8-10].Among the alloys,Ni-Mn-Sn-based alloys are environment-friendly and cost-effective[6,7,11],and hence,they have received widespread attention.展开更多
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
Natural organic matter(NOM)containing Fe/Mn(hydr)oxides effectively stabilizes antimony(Sb)and arsenic(As)in soils.However,the specific type of NOM that limits the mobility of Fe/Mn(hydr)oxides and howNOM-Fe/Mn colloi...Natural organic matter(NOM)containing Fe/Mn(hydr)oxides effectively stabilizes antimony(Sb)and arsenic(As)in soils.However,the specific type of NOM that limits the mobility of Fe/Mn(hydr)oxides and howNOM-Fe/Mn colloidal properties can bemodulated for better Sb and As stabilization remains unclear.This study suggests that the degree of stabilization of the colloidal structure formed between NOM and Fe/Mn(hydr)oxides is crucial for Sb and As stabilization.It was found that straw-derived(SD),compared to humic acid(HA)with a high content of carboxyl groups,forms more stable colloidal structures with Fe/Mn(hydr)oxides.HA-Fe/Mn colloids show greater mobility and less deposition than SD-Fe/Mn colloids.In soil remediation simulations,SD-Fe/Mn colloids more effectively stabilized Sb and As.After 35 days,SD-Fe/Mn achieved nearly complete stabilization(100%)of water-soluble and decarbonate-extracted bioavailable fractions at depths of 1-12 cm,with high rates for other fractions as well.Even at depths of 23-34 cm,SD-Fe/Mn outperformed HA-Fe/Mn,showing higher stabilization rates for Sb and As by 12.6%and 20.4%,respectively.Morphological analysis suggests that the stabilization of Sb and As by SD-Fe/Mn primarily involves adsorption onto or incorporation within the Fe/Mn(hydr)oxides.This study offers guidance for optimizing NOM-Fe/Mn for in situ stabilization of Sb and As,enhances the understanding of different types of NOM that affect the behavior of Sb and As soil contamination,and presents new perspectives for developing effective in situ remediation materials.展开更多
Co-V-Ga-based shape memory alloys have shown great potential in the field of solid-state elastocaloric refrigeration due to their low stress hysteresis(Δσ_(hys)) and excellent superelasticity.However,large applied s...Co-V-Ga-based shape memory alloys have shown great potential in the field of solid-state elastocaloric refrigeration due to their low stress hysteresis(Δσ_(hys)) and excellent superelasticity.However,large applied stress and low adiabatic temperature change(ΔT_(ad)) greatly limit the application of Co-V-Ga-based alloys as elastocaloric materials.Here,we have successfully achieved a breakthrough in material properties by innovatively introducing the co-doping strategy of Mn and Ti elements.It was found that the synergistic effect of Mn and Ti significantly enhanced the mechanical properties of the Co_(52)V_(31)Ga_(14)Mn_(1)Ti_(2) alloy through solid solution strengthening,fine grain strengthening,and precipitation strengthening mechanisms.A large ΔT_(ad) of-11 K was obtained for the Co_(52)V_(31)Ga_(14)Mn_(1)Ti_(2) bulk poly crystalline alloy under a very low applied stress of 380 MPa.This is mainly due to the strong texture of <001>A.Texture strengthening is the key factor to improve the elastocaloric effect of alloys.At the same time,the Co_(52)V_(31)Ga_(14)Mn_(1)Ti_(2) alloy still maintains a ΔT_(ad) of -4 K without an obvious attenuation trend after 350 elastocaloric cycles under the applied stress of 300 MPa.In addition,due to the low energy dissipation(ΔW),the energy conversion efficiency of the elastocaloric response is greatly improved,so that the coefficient of performance(COP) of the Co_(52)V_(31)Ga_(14)Mn_(1)Ti_(2) alloy material is as high as 28.9,far exceeding most of the current shape memory alloy elastocaloric materials.As a result,the co-doping of Mn and Ti elements makes it possible to prepare an elastocaloric refrigeration alloy with low applied stress and a large elastocaloric effect.展开更多
CaO-based heat carriers have shown great prospects for thermochemical energy storage in concentrated solar power systems due to the features such as rich reserves,environmental safety,high energy storage densities and...CaO-based heat carriers have shown great prospects for thermochemical energy storage in concentrated solar power systems due to the features such as rich reserves,environmental safety,high energy storage densities and high operation temperatures.However,the density decay because of sintering and poor direct solar absorption of white CaO based heat carriers are the two main obstacles lying on the way to the realistic applications.This work introduced dark Mn-based inert support into calcium heat carriers,attempting to solve the above problems simultaneously.As an inert support,the finely dispersed Ca_(2)MnO_(4) functioned as the metal framework to resist CaCO_(3)/CaO sintering.Consequently,the cyclic stability of CaO-based heat carriers,resulting in the high energy storage densities of~2000 kJ/kg even over 20 cycles.As a dark material,Ca_(2)MnO_(4) successfully darkened CaO-based heat carriers,thereby greatly enhanced the direct solar absorption.In addition,the granulation of CaO-based heat carriers was also studied.The pellets showed satisfactory attrition resistance with only 9.85 wt% mass loss over 3200 cycles.In general,good physicochemical performance of Mn-doped CaO-based heat carrier endows it with great prospects for solar energy storage.展开更多
Toxoplasma gondii is a single-celled parasite that infects nearly all warm-blooded animals,including humans(Montoya and Liesenfeld,2004).It occurs worldwide and can persist for a lifetime in mammals.Humans get infecte...Toxoplasma gondii is a single-celled parasite that infects nearly all warm-blooded animals,including humans(Montoya and Liesenfeld,2004).It occurs worldwide and can persist for a lifetime in mammals.Humans get infected by eating undercooked meat of animals containing the tissue cysts of this parasite.In immune-competent individuals,T.展开更多
With the laser remelting of cast alloys combined with non-equilibrium liquidus projection thermodynamic calculations,a high-strength and heat-resistant Al-3Fe-2Mn alloy was designed.Incorporating Mn atoms into the met...With the laser remelting of cast alloys combined with non-equilibrium liquidus projection thermodynamic calculations,a high-strength and heat-resistant Al-3Fe-2Mn alloy was designed.Incorporating Mn atoms into the metastable nanoscale Al_(6)Fe phase,occupying some lattice sites,enhances its thermal stability.Additionally,during rapid solidification of laser powder bed fusion(L-PBF),the solubility of Fe and Mn elements in the aluminum alloy increases significantly,forming a supersaturated solid solution with improved strength.This alloy demonstrates excellent processability,achieving a relative density of over 99%,and tensile strengths of 295 MPa at 200℃ and 230 MPa at 300℃.The Al-3Fe-2Mn alloy holds great potential for wide applications due to its high strength at high temperature.展开更多
As a representative of the third generation advanced high-strength steels(AHSSs),medium Mn steels(MMS)have broad development prospects in the field of automobile manufacturing.MMS with typical austenite reversion trea...As a representative of the third generation advanced high-strength steels(AHSSs),medium Mn steels(MMS)have broad development prospects in the field of automobile manufacturing.MMS with typical austenite reversion treatment have a soft duplex microstructure,i.e.ferrite+austenite,presenting a high ductility but a low yield strength.Here we show that a flash heating and cooling after austenite reversion treatment can replace the ferrite with strong martensite,which greatly enhances the yield strength of a 0.25C-4Mn steel by about 461–886 MPa.By adjusting the reversion temperature before the flash treatment,the C and Mn concentrations of reverted austenite can be altered,which determine the fraction of reverted austenite surviving the flash treatment.In addition,the mechanical stability of final retained austenite is also linked to the reversion temperature,resulting different work hardening behaviors due to transformation induced plasticity(TRIP)effect.By tweaking the reversion temperature before the flash treatment,an optimized combination of strength and ductility can be achieved.The micromechanical differences caused by the replacement of the matrix are also investigated via in-situ digital image correlation method.展开更多
Al−3.51Mg−0.42Mn−0.76Sc−0.40Zr(wt.%)alloy was prepared by selective laser melting(SLM)method.The mechanical properties and microstructure of the alloy after annealing at 300℃or 325℃for 6 h were studied.The tensile s...Al−3.51Mg−0.42Mn−0.76Sc−0.40Zr(wt.%)alloy was prepared by selective laser melting(SLM)method.The mechanical properties and microstructure of the alloy after annealing at 300℃or 325℃for 6 h were studied.The tensile strength,yield strength and elongation of the SLM alloy were 339 MPa,213 MPa and 24%,respectively.After annealing at 300℃for 6 h,the tensile and yield strength of the alloy were increased to 518 MPa and 505 MPa,respectively,and the elongation decreased to 13%.After annealing at 325℃for 6 h,the yield strength of the alloy was reduced to 483 MPa.The grain size of the alloy after annealing at 300℃and 325℃did not grow significantly,but the segregation of Mg element was significantly reduced.Nanoscale Al3(Sc,Zr)phase was precipitated from the alloy matrix,and its average size increased with the increase of annealing temperature.Therefore,the strength improvement of the annealed SLM aluminum alloy was mainly attributed to the precipitation strengthening of Al3(Sc,Zr),and the strengthening mechanism was mainly dislocation cutting mechanism.When the annealing temperature was too high,the coarsening of Al3(Sc,Zr)particles caused the strength to decrease.展开更多
To improve the processability and mechanical properties of the selective laser melting(SLM)low Sc content Al−Mg−Sc−Zr alloy,Mn was used to partially replace Mg.The processability,microstructure,and mechanical properti...To improve the processability and mechanical properties of the selective laser melting(SLM)low Sc content Al−Mg−Sc−Zr alloy,Mn was used to partially replace Mg.The processability,microstructure,and mechanical properties of the SLM-fabricated Al−Mg−Mn−Sc−Zr alloy were systematically investigated by density measurement,microstructure characterization,and tensile testing.The results revealed that dense samples could be obtained by adjusting the SLM process parameters.The alloy exhibited a fine equiaxed-columnar bimodal grain microstructure.The presence of primary Al3Sc andα-Al(Mn,Fe)Si particles contributed to the grain refinement of the alloy with an average grain size of 4.63μm.Upon aging treatment at 350°C for 2 h,the strength and elongation of the alloy were simultaneously improved due to the precipitation of Al3Sc nanoparticles and the formation of the 9R phase.This study demonstrates that the strength−plasticity trade-off of the aluminum alloy can be overcome by utilizing SLM technology and subsequent post-heat treatment to induce the formation of the long-period stacked ordered phase.展开更多
The microstructural evolution of Cu−19Ni−6Cr−7Mn alloy during aging treatment was investigated.After aging for 120 min at 500℃,the alloy exhibited excellent mechanical properties,including a tensile strength of 978 M...The microstructural evolution of Cu−19Ni−6Cr−7Mn alloy during aging treatment was investigated.After aging for 120 min at 500℃,the alloy exhibited excellent mechanical properties,including a tensile strength of 978 MPa and an elastic modulus of 145.8 GPa.After aging for 240 min at 500℃,the elastic modulus of the alloy reached 149.5 GPa,which was among the highest values reported for Cu alloys.It was worth mentioning that the tensile strength increased rapidly from 740 to 934 MPa after aging for 5 min at 500℃,which was close to the maximum tensile strength(978 MPa).Analysis of the underlying strengthening mechanisms and phase transformation behavior revealed that the Cu−19Ni−6Cr−7Mn alloy underwent spinodal decomposition and DO_(22) ordering during the first 5 min of aging at 500℃,and L1_(2) ordered phases and bcc-Cr precipitates appeared.Therefore,the enhanced mechanical properties of the Cu−19Ni−6Cr−7Mn alloy can be attributed to the stress field generated by spinodal decomposition and the presence of nanoscale ordered phase and Cr precipitates.展开更多
The effects of artificial aging(T6)on the creep resistance with tensile stresses in the range of 50−80 MPa at 175℃were investigated for an extruded Mg−1.22Al−0.31Ca−0.44Mn(wt.%)alloy.The Guinier-Preston(G.P.)zones pr...The effects of artificial aging(T6)on the creep resistance with tensile stresses in the range of 50−80 MPa at 175℃were investigated for an extruded Mg−1.22Al−0.31Ca−0.44Mn(wt.%)alloy.The Guinier-Preston(G.P.)zones primarily precipitate in the sample aged at 200℃for 1 h(T6-200℃/1h),while the Al_(2)Ca phases mainly precipitate in the sample aged at 275℃for 8 h(T6-275℃/8h).The T6-200℃/1h sample exhibits excellent creep resistance,with a steady-state creep rate one order of magnitude lower than that of the T6-275℃/8h sample.The abnormally high stress exponent(~8.2)observed in the T6-200℃/1h sample is associated with the power-law breakdown mechanism.TEM analysis illuminates that the creep mechanism for the T6-200℃/1h sample is cross-slip between basal and prismatic dislocations,while the T6-275℃/8h sample exhibits a mixed mechanism of dislocation cross-slip and climb.Compared with the Al_(2)Ca phase,the dense G.P.zones effectively impede dislocation climb and glide during the creep process,demonstrating superior creep resistance of the T6-200℃/1h sample.展开更多
基金financially supported by the Shandong Provincial Natural Science Foundation(ZR2023LFG005)the National Natural Science Foundation of China(Nos.22479161,52274308 and U22B20144)the Fundamental Research Funds for the Central Universities(No.24CX03012A)。
文摘Non-precious metal cobalt-based oxide inevitably dissolves for acid oxygen evolution reaction(OER).Designing an efficient deposition channel for leaching cobalt species is a promising approach.The dissolution-deposition equilibrium of Co is achieved by doping Mn in the lattice of LaCo_(1-x)Mn_(x)O_(3),prolonging the lifespan in acidic conditions by 14 times.The lattice doping of Mn produces a strain that enhances the adsorption capacity of OH^(-).The self-catalysis of Mn causes the leaching Co to be deposited in the form of CoO_(2),which ensures that the long-term stability of LaCo_(1-x)Mn_(x)O_(3)is 70 h instead of 5 h for LaCoO_(3).Mn doping enhances the deprotonation of^(*)OOH→O_(2)in acidic environments.Notably,the over-potential of optimized LaCo_(1-x)Mn_(x)O_(3)is 345 mV at 10 mA cm^(-2)for acidic OER.This work presents a promising method for developing noble metal-free catalysts that enhance the acidic OER activity and stability.
基金supported by the National Key R&D Pro-gram of China(No.2022YFB3805701)National Natural Science Foundation of China(NSFC)(No.52371182,51701052,52192592,52192593)+1 种基金Young Elite Scientists Sponsorship Program by CAST(No.2019QNRC001)the Heilongjiang Touyan Innovation Team Program.
文摘1.Introduction.Ni-Mn-X(X=Ga,In,Sn,or Sb)Heusler alloys have versatile properties[1-4],such as shape memory effect[1],superelastic-ity[5],magnetocaloric effect[3],elastocaloric effect[6],and even multicaloric effect[7],that indicate their potential for use in actu-ators,sensors,micropumps,energy harvesters,and solid-state re-frigeration[8-10].Among the alloys,Ni-Mn-Sn-based alloys are environment-friendly and cost-effective[6,7,11],and hence,they have received widespread attention.
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supported by the National Natural Science Foundation of China(No.U23A20679)the Natural Science Foundation of Hunan Province(No.2023JJ0065)+1 种基金the Foundation for Innovative Research Groups of the National Natural Science Foundation of China(No.52121004)the Key Research and Development Project of the Power Construction Corporation of China(No.DJ-ZDXM-2023-24).
文摘Natural organic matter(NOM)containing Fe/Mn(hydr)oxides effectively stabilizes antimony(Sb)and arsenic(As)in soils.However,the specific type of NOM that limits the mobility of Fe/Mn(hydr)oxides and howNOM-Fe/Mn colloidal properties can bemodulated for better Sb and As stabilization remains unclear.This study suggests that the degree of stabilization of the colloidal structure formed between NOM and Fe/Mn(hydr)oxides is crucial for Sb and As stabilization.It was found that straw-derived(SD),compared to humic acid(HA)with a high content of carboxyl groups,forms more stable colloidal structures with Fe/Mn(hydr)oxides.HA-Fe/Mn colloids show greater mobility and less deposition than SD-Fe/Mn colloids.In soil remediation simulations,SD-Fe/Mn colloids more effectively stabilized Sb and As.After 35 days,SD-Fe/Mn achieved nearly complete stabilization(100%)of water-soluble and decarbonate-extracted bioavailable fractions at depths of 1-12 cm,with high rates for other fractions as well.Even at depths of 23-34 cm,SD-Fe/Mn outperformed HA-Fe/Mn,showing higher stabilization rates for Sb and As by 12.6%and 20.4%,respectively.Morphological analysis suggests that the stabilization of Sb and As by SD-Fe/Mn primarily involves adsorption onto or incorporation within the Fe/Mn(hydr)oxides.This study offers guidance for optimizing NOM-Fe/Mn for in situ stabilization of Sb and As,enhances the understanding of different types of NOM that affect the behavior of Sb and As soil contamination,and presents new perspectives for developing effective in situ remediation materials.
基金financially supported by the National Natural Science Foundation of China(Nos.52271172 and 51971085)Heilongjiang Provincial Natural Science Foundation of China(No.LH2024E075)
文摘Co-V-Ga-based shape memory alloys have shown great potential in the field of solid-state elastocaloric refrigeration due to their low stress hysteresis(Δσ_(hys)) and excellent superelasticity.However,large applied stress and low adiabatic temperature change(ΔT_(ad)) greatly limit the application of Co-V-Ga-based alloys as elastocaloric materials.Here,we have successfully achieved a breakthrough in material properties by innovatively introducing the co-doping strategy of Mn and Ti elements.It was found that the synergistic effect of Mn and Ti significantly enhanced the mechanical properties of the Co_(52)V_(31)Ga_(14)Mn_(1)Ti_(2) alloy through solid solution strengthening,fine grain strengthening,and precipitation strengthening mechanisms.A large ΔT_(ad) of-11 K was obtained for the Co_(52)V_(31)Ga_(14)Mn_(1)Ti_(2) bulk poly crystalline alloy under a very low applied stress of 380 MPa.This is mainly due to the strong texture of <001>A.Texture strengthening is the key factor to improve the elastocaloric effect of alloys.At the same time,the Co_(52)V_(31)Ga_(14)Mn_(1)Ti_(2) alloy still maintains a ΔT_(ad) of -4 K without an obvious attenuation trend after 350 elastocaloric cycles under the applied stress of 300 MPa.In addition,due to the low energy dissipation(ΔW),the energy conversion efficiency of the elastocaloric response is greatly improved,so that the coefficient of performance(COP) of the Co_(52)V_(31)Ga_(14)Mn_(1)Ti_(2) alloy material is as high as 28.9,far exceeding most of the current shape memory alloy elastocaloric materials.As a result,the co-doping of Mn and Ti elements makes it possible to prepare an elastocaloric refrigeration alloy with low applied stress and a large elastocaloric effect.
基金Project(2024BAB094)supported by the Key Research and Development Program of Hubei Province,ChinaProject(2024040801020296)supported by the Natural Science Foundation of Wuhan City,ChinaProject(52276113)supported by the National Natural Science Foundation of China。
文摘CaO-based heat carriers have shown great prospects for thermochemical energy storage in concentrated solar power systems due to the features such as rich reserves,environmental safety,high energy storage densities and high operation temperatures.However,the density decay because of sintering and poor direct solar absorption of white CaO based heat carriers are the two main obstacles lying on the way to the realistic applications.This work introduced dark Mn-based inert support into calcium heat carriers,attempting to solve the above problems simultaneously.As an inert support,the finely dispersed Ca_(2)MnO_(4) functioned as the metal framework to resist CaCO_(3)/CaO sintering.Consequently,the cyclic stability of CaO-based heat carriers,resulting in the high energy storage densities of~2000 kJ/kg even over 20 cycles.As a dark material,Ca_(2)MnO_(4) successfully darkened CaO-based heat carriers,thereby greatly enhanced the direct solar absorption.In addition,the granulation of CaO-based heat carriers was also studied.The pellets showed satisfactory attrition resistance with only 9.85 wt% mass loss over 3200 cycles.In general,good physicochemical performance of Mn-doped CaO-based heat carrier endows it with great prospects for solar energy storage.
基金supported by the National Natural Sci ence Foundation of China(No.31672543)the Zhejiang Province“Sannongliufang”Science and Technology Coopera tion Project(No.2020SNLF007),China.
文摘Toxoplasma gondii is a single-celled parasite that infects nearly all warm-blooded animals,including humans(Montoya and Liesenfeld,2004).It occurs worldwide and can persist for a lifetime in mammals.Humans get infected by eating undercooked meat of animals containing the tissue cysts of this parasite.In immune-competent individuals,T.
基金supported by the National Natural Science Foundation of China(No.U21B2073)the Science and Technology Project of the Science and Technology Department of Hubei Province,China(No.2022EHB020)。
文摘With the laser remelting of cast alloys combined with non-equilibrium liquidus projection thermodynamic calculations,a high-strength and heat-resistant Al-3Fe-2Mn alloy was designed.Incorporating Mn atoms into the metastable nanoscale Al_(6)Fe phase,occupying some lattice sites,enhances its thermal stability.Additionally,during rapid solidification of laser powder bed fusion(L-PBF),the solubility of Fe and Mn elements in the aluminum alloy increases significantly,forming a supersaturated solid solution with improved strength.This alloy demonstrates excellent processability,achieving a relative density of over 99%,and tensile strengths of 295 MPa at 200℃ and 230 MPa at 300℃.The Al-3Fe-2Mn alloy holds great potential for wide applications due to its high strength at high temperature.
基金National Key R&D Program of China(Grant Nos.2022YFE0110800 and 2022YFB3705300)the National Natural Science Foundation of China(Grant Nos.52104380 and 52171123)for grant and financial support.
文摘As a representative of the third generation advanced high-strength steels(AHSSs),medium Mn steels(MMS)have broad development prospects in the field of automobile manufacturing.MMS with typical austenite reversion treatment have a soft duplex microstructure,i.e.ferrite+austenite,presenting a high ductility but a low yield strength.Here we show that a flash heating and cooling after austenite reversion treatment can replace the ferrite with strong martensite,which greatly enhances the yield strength of a 0.25C-4Mn steel by about 461–886 MPa.By adjusting the reversion temperature before the flash treatment,the C and Mn concentrations of reverted austenite can be altered,which determine the fraction of reverted austenite surviving the flash treatment.In addition,the mechanical stability of final retained austenite is also linked to the reversion temperature,resulting different work hardening behaviors due to transformation induced plasticity(TRIP)effect.By tweaking the reversion temperature before the flash treatment,an optimized combination of strength and ductility can be achieved.The micromechanical differences caused by the replacement of the matrix are also investigated via in-situ digital image correlation method.
基金financially supported by the National Key Research and Development Program of China(No.2018YFB2001801)State’s Key Project of Research and Development Plan(No.2021YFC1910505)the Key Research and Development Program of Guangdong Province,China(No.2020B010186002)。
文摘Al−3.51Mg−0.42Mn−0.76Sc−0.40Zr(wt.%)alloy was prepared by selective laser melting(SLM)method.The mechanical properties and microstructure of the alloy after annealing at 300℃or 325℃for 6 h were studied.The tensile strength,yield strength and elongation of the SLM alloy were 339 MPa,213 MPa and 24%,respectively.After annealing at 300℃for 6 h,the tensile and yield strength of the alloy were increased to 518 MPa and 505 MPa,respectively,and the elongation decreased to 13%.After annealing at 325℃for 6 h,the yield strength of the alloy was reduced to 483 MPa.The grain size of the alloy after annealing at 300℃and 325℃did not grow significantly,but the segregation of Mg element was significantly reduced.Nanoscale Al3(Sc,Zr)phase was precipitated from the alloy matrix,and its average size increased with the increase of annealing temperature.Therefore,the strength improvement of the annealed SLM aluminum alloy was mainly attributed to the precipitation strengthening of Al3(Sc,Zr),and the strengthening mechanism was mainly dislocation cutting mechanism.When the annealing temperature was too high,the coarsening of Al3(Sc,Zr)particles caused the strength to decrease.
基金supported by the National Natural Science Foundation of China(Nos.51801079,52001140)the National Funds Through FCT of Portugal–Fundacao para a Ciência e a Tecnologia,under a scientific contract of 2021.04115.CEECIND,and the Projects of UIDB/00285/2020,and LA/0112/2020。
文摘To improve the processability and mechanical properties of the selective laser melting(SLM)low Sc content Al−Mg−Sc−Zr alloy,Mn was used to partially replace Mg.The processability,microstructure,and mechanical properties of the SLM-fabricated Al−Mg−Mn−Sc−Zr alloy were systematically investigated by density measurement,microstructure characterization,and tensile testing.The results revealed that dense samples could be obtained by adjusting the SLM process parameters.The alloy exhibited a fine equiaxed-columnar bimodal grain microstructure.The presence of primary Al3Sc andα-Al(Mn,Fe)Si particles contributed to the grain refinement of the alloy with an average grain size of 4.63μm.Upon aging treatment at 350°C for 2 h,the strength and elongation of the alloy were simultaneously improved due to the precipitation of Al3Sc nanoparticles and the formation of the 9R phase.This study demonstrates that the strength−plasticity trade-off of the aluminum alloy can be overcome by utilizing SLM technology and subsequent post-heat treatment to induce the formation of the long-period stacked ordered phase.
基金supported by the National Key R&D Program of China (No. 2021YFB3700700)the Henan Province Top Talent Training Program Project, China (No. 244500510020)the High-level Talent Research Start-up Project Funding of Henan Academy of Sciences, China (No. 242017001)。
文摘The microstructural evolution of Cu−19Ni−6Cr−7Mn alloy during aging treatment was investigated.After aging for 120 min at 500℃,the alloy exhibited excellent mechanical properties,including a tensile strength of 978 MPa and an elastic modulus of 145.8 GPa.After aging for 240 min at 500℃,the elastic modulus of the alloy reached 149.5 GPa,which was among the highest values reported for Cu alloys.It was worth mentioning that the tensile strength increased rapidly from 740 to 934 MPa after aging for 5 min at 500℃,which was close to the maximum tensile strength(978 MPa).Analysis of the underlying strengthening mechanisms and phase transformation behavior revealed that the Cu−19Ni−6Cr−7Mn alloy underwent spinodal decomposition and DO_(22) ordering during the first 5 min of aging at 500℃,and L1_(2) ordered phases and bcc-Cr precipitates appeared.Therefore,the enhanced mechanical properties of the Cu−19Ni−6Cr−7Mn alloy can be attributed to the stress field generated by spinodal decomposition and the presence of nanoscale ordered phase and Cr precipitates.
基金supported by the National Natural Science Foundation of China (Nos. 52175322, 52271031)the Natural Science Foundation of Jilin Province, China (No. SKL202302015)。
文摘The effects of artificial aging(T6)on the creep resistance with tensile stresses in the range of 50−80 MPa at 175℃were investigated for an extruded Mg−1.22Al−0.31Ca−0.44Mn(wt.%)alloy.The Guinier-Preston(G.P.)zones primarily precipitate in the sample aged at 200℃for 1 h(T6-200℃/1h),while the Al_(2)Ca phases mainly precipitate in the sample aged at 275℃for 8 h(T6-275℃/8h).The T6-200℃/1h sample exhibits excellent creep resistance,with a steady-state creep rate one order of magnitude lower than that of the T6-275℃/8h sample.The abnormally high stress exponent(~8.2)observed in the T6-200℃/1h sample is associated with the power-law breakdown mechanism.TEM analysis illuminates that the creep mechanism for the T6-200℃/1h sample is cross-slip between basal and prismatic dislocations,while the T6-275℃/8h sample exhibits a mixed mechanism of dislocation cross-slip and climb.Compared with the Al_(2)Ca phase,the dense G.P.zones effectively impede dislocation climb and glide during the creep process,demonstrating superior creep resistance of the T6-200℃/1h sample.
