Micro-alloying design of wrought magnesium(Mg) alloys is an important strategy to achieve high mechanical properties at a low cost. In the last two decades, significant progress has been made from both theory and expe...Micro-alloying design of wrought magnesium(Mg) alloys is an important strategy to achieve high mechanical properties at a low cost. In the last two decades, significant progress has been made from both theory and experiment. In the present review, we try to summarize recent advances in micro-alloying design of wrought Mg alloys from both theoretical and pragmatic perspectives, and provide fundamental data required for establishing the relationship between chemical composition and mechanical properties of Mg alloys. We start with theoretical attempts for understanding the mechanical properties of Mg alloys at different scales, by involving first principle calculations,molecular dynamics, cellular automata, and crystal plasticity. Then, the role of alloying elements is discussed for a series of promising Mg alloys such as Mg-Al, Mg-Zn, Mg-RE(rare-earth element), Mg-Sn, and Mg-Ca families.Potential challenges in the micro-alloying design of Mg alloys are highlighted at the end. The review is expected to provide helpful guidance for the intelligent design of novel wrought Mg alloys and inspire more innovative ideas in this field.展开更多
Mg-Sn-Y alloys with different Sn contents(wt%)were assessed as anode candidates for Mg-air batteries.The relationship between microstructure(including the second phase,grain size,and texture)and discharge properties o...Mg-Sn-Y alloys with different Sn contents(wt%)were assessed as anode candidates for Mg-air batteries.The relationship between microstructure(including the second phase,grain size,and texture)and discharge properties of the Mg-Sn-Y alloys was examined using microstructure observation,electrochemical measurements,and galvanostatic discharge tests.The Mg-0.7Sn-1.4Y alloy had a high steady discharge voltage of 1.5225 V and a high anodic efficiency of 46.6% at 2.5 mA·cm^(-2).These good properties were related to its microstructure:small grain size of 3.8μm,uniform distribution of small second phase particles of 0.6μm,and a high content(vol%)of(1120)/(1010)orientated grains.The scanning Kelvin probe force microscopy(SKPFM)indicated that the Sn_(3)Y_(5) and MgSnY phases were effective cathodes causing micro-galvanic corrosion which promoted the dissolution of Mg matrix during the discharge process.展开更多
In order to analyze the effect of scratch on the corrosion behaviour of a calcium phosphate conversion coating(CPCC)on AZ80,the electrochemical testing,scanning vibrating electrode technique(SVET),immersion test and h...In order to analyze the effect of scratch on the corrosion behaviour of a calcium phosphate conversion coating(CPCC)on AZ80,the electrochemical testing,scanning vibrating electrode technique(SVET),immersion test and hydrogen evolution experiment were performed to study the corrosion resistance of AZ80,AZ80 with CPCC and coated AZ80 with scratch.The results show that the coating improves the corrosion resistance of the AZ80 from a current density of(85±4)to(4±1)μA/cm^(2).When the coating was damaged,its protection on substrate would be reduced.The scratch with a length of around 12 mm on the coating reduced the corrosion resistance to a current density of(39±1)μA/cm^(2).In addition,the corrosion occurred initially in the scratch area and the corrosion site first occurred at the junction of the scratch and the coating.Besides,the micro corrosion mechanism of the specimen containing scratch was clarified.展开更多
Mg−Al layered double hydroxides(LDHs),produced on cast Mg−xCa(x=0.5,0.8,2.0,wt.%)alloys by an in-situ growth method,showed good corrosion resistance compared to the bare magnesium substrate.The influence mechanism of ...Mg−Al layered double hydroxides(LDHs),produced on cast Mg−xCa(x=0.5,0.8,2.0,wt.%)alloys by an in-situ growth method,showed good corrosion resistance compared to the bare magnesium substrate.The influence mechanism of the second phase(Mg_(2)Ca)on LDHs production was investigated.Increasing Ca content increased the amount of Mg_(2)Ca,decreasing the grain size and the corrosion rate of the alloys.The increased amount of the second phase particles and the grain refinement promoted the growth of LDHs,and thus led to the decreasing of corrosion rate of the Mg−xCa alloys with LDHs.A higher Mg_(2)Ca amount resulted in forming fluffy LDHs.Due to the dual effects of the second phase(Mg_(2)Ca)for LDHs growth and microgalvanic corrosion,LDHs/Mg−0.8Ca showed the lowest corrosion rate.展开更多
Effects of Zn content (0, 0.5%, 1.5% and 4.5%) on the hot tearing characteristics of Mg?2%Y alloy were studied in aconstrained rod casting (CRC) apparatus attached with a load cell and data acquisition system. The exp...Effects of Zn content (0, 0.5%, 1.5% and 4.5%) on the hot tearing characteristics of Mg?2%Y alloy were studied in aconstrained rod casting (CRC) apparatus attached with a load cell and data acquisition system. The experimental results indicate thatthe hot tearing susceptibility (HTS) is affected by the content of Zn. The Zn-free base alloy shows the lowest HTS. The HTS ofMg?xZn?2Y alloys increases with increasing Zn content, reaches the maximum at 1.5% Zn, and then decreases with further Znaddition. The high HTS observed in the alloy with 1.5% Zn is attributed to its high force release rate and large force drop duringsolidification. The hot cracks of casting are initiated and propagate along the dendritic or grain boundaries. The predictions of HTS ofMg?xZn?2Y alloys using ProCAST software are in good agreement with the results obtained by experimental measurements.展开更多
Edge cracking is one of the most serious problems in the rolling process of magnesium alloy sheets,which limits its application.In this work,the edge cracking behavior of different initial AZ31 alloy sheets,including ...Edge cracking is one of the most serious problems in the rolling process of magnesium alloy sheets,which limits its application.In this work,the edge cracking behavior of different initial AZ31 alloy sheets,including as-cast(AC),as-rolled(AR)and as-extruded(AE),was systematically investigated and compared under the online heating rolling(O-LHR)process with a single-pass reduction of 50% at 250℃.The results show that both AC and AR sheets exhibit severe edge cracking behavior after the O-LHR.Among them,the AR sheet exhibits the severest edge cracking behavior on the rolling plane(RD-TD)and longitudinal section(RD-ND),which is attributed to the strong basal texture and extremely uneven microstructure with shear bands.While no visible edge crack appears in the AE rolled sheet,which is mainly related to the tilted texture and the more dynamic recrystallization during rolling process.Moreover,it is also found that the micro-cracks of the AC rolled sheet are mainly generated in the local fine-grained area and the twins where recrystallization occurs.In the AR rolled sheet,micro-cracks mainly develop inside the shear bands.Meanwhile,the micro-crack initiation mechanism of AC and AR rolled sheets was also discussed.展开更多
Separating high-purity hydrogen isotopes from their mixture still remains a huge challenge due to almost the identical physicochemical properties.Much importance has been attached to tune microstructure of porous mate...Separating high-purity hydrogen isotopes from their mixture still remains a huge challenge due to almost the identical physicochemical properties.Much importance has been attached to tune microstructure of porous materials,while heat management during hydrogen isotope separation tends to be ignored.Herein,a porous material 5 A molecular sieve(5 A)is mixed with graphene(GE)under ball grinding to enhance its thermal conductivity for hydrogen isotope separation.The thermal conductivity increases from 0.19 W m^(-1)K^(-1)of neat 5 A,0.75 W m^(-1)K^(-1)of 5 A/GE2(2 wt%GE)to 1.23 W m^(-1)K^(-1)of 5 A/GE8.In addition,introducing GE into 5 A promotes hydrogen adsorption and D_(2)/H_(2)adsorption ratio.5 A/GE2 shows the highest D_(2)adsorption capacity(5.40 mmol/g)and the largest D_(2)/H_(2)adsorption ratio(1.07)among the composites.It also displays a high efficiency of heat transfer that contributes to a low energy consumption due to the shortened cycle time during hydrogen isotope separation.This work offers new insights into material design for improved hydrogen isotope separation,which is greatly crucial to scientific and industrial applications,such as fuel self-sustaining in fusion reactors.展开更多
基金the financial supports from the National Natural Science Foundation of China (Nos. U1764253, U2037601, 52001037, 51971044, 52101126)the National Defense Basic Scientific Research Program of China, China Postdoctoral Science Foundation (No. 2021M700566)+3 种基金the Natural Science Foundation of Chongqing, China (No. cstc2019jcyjmsxm X0234)Chongqing Science and Technology Commission, China (No. cstc2017zdcyzdzx X0006)Chongqing Scientific and Technological Talents Program, China (No. KJXX2017002)Qinghai Science and Technology Program, China (No. 2018-GX-A1)。
文摘Micro-alloying design of wrought magnesium(Mg) alloys is an important strategy to achieve high mechanical properties at a low cost. In the last two decades, significant progress has been made from both theory and experiment. In the present review, we try to summarize recent advances in micro-alloying design of wrought Mg alloys from both theoretical and pragmatic perspectives, and provide fundamental data required for establishing the relationship between chemical composition and mechanical properties of Mg alloys. We start with theoretical attempts for understanding the mechanical properties of Mg alloys at different scales, by involving first principle calculations,molecular dynamics, cellular automata, and crystal plasticity. Then, the role of alloying elements is discussed for a series of promising Mg alloys such as Mg-Al, Mg-Zn, Mg-RE(rare-earth element), Mg-Sn, and Mg-Ca families.Potential challenges in the micro-alloying design of Mg alloys are highlighted at the end. The review is expected to provide helpful guidance for the intelligent design of novel wrought Mg alloys and inspire more innovative ideas in this field.
文摘Mg-Sn-Y alloys with different Sn contents(wt%)were assessed as anode candidates for Mg-air batteries.The relationship between microstructure(including the second phase,grain size,and texture)and discharge properties of the Mg-Sn-Y alloys was examined using microstructure observation,electrochemical measurements,and galvanostatic discharge tests.The Mg-0.7Sn-1.4Y alloy had a high steady discharge voltage of 1.5225 V and a high anodic efficiency of 46.6% at 2.5 mA·cm^(-2).These good properties were related to its microstructure:small grain size of 3.8μm,uniform distribution of small second phase particles of 0.6μm,and a high content(vol%)of(1120)/(1010)orientated grains.The scanning Kelvin probe force microscopy(SKPFM)indicated that the Sn_(3)Y_(5) and MgSnY phases were effective cathodes causing micro-galvanic corrosion which promoted the dissolution of Mg matrix during the discharge process.
基金financially supported by the National Natural Science Foundation of China(Nos.52071036,51701027)the Fundamental Research Funds for the Central Universities,China(Nos.2020CDJQY-A002,2021CDJCGJ009)the National Key Research and Development Program of China(Nos.2016YFB0301100,2016YFB0101700)。
文摘In order to analyze the effect of scratch on the corrosion behaviour of a calcium phosphate conversion coating(CPCC)on AZ80,the electrochemical testing,scanning vibrating electrode technique(SVET),immersion test and hydrogen evolution experiment were performed to study the corrosion resistance of AZ80,AZ80 with CPCC and coated AZ80 with scratch.The results show that the coating improves the corrosion resistance of the AZ80 from a current density of(85±4)to(4±1)μA/cm^(2).When the coating was damaged,its protection on substrate would be reduced.The scratch with a length of around 12 mm on the coating reduced the corrosion resistance to a current density of(39±1)μA/cm^(2).In addition,the corrosion occurred initially in the scratch area and the corrosion site first occurred at the junction of the scratch and the coating.Besides,the micro corrosion mechanism of the specimen containing scratch was clarified.
基金supported by the National Natural Science Foundation of China(No.51971040)the Fundamental Research Funds for the Central Universities,China(No.2020CDJQY-A007)+1 种基金China Postdoctoral Science Foundation(Nos.2017M620410,2018T110942)the Chongqing Postdoctoral Scientific Research Foundation,China(No.Xm2017010).
文摘Mg−Al layered double hydroxides(LDHs),produced on cast Mg−xCa(x=0.5,0.8,2.0,wt.%)alloys by an in-situ growth method,showed good corrosion resistance compared to the bare magnesium substrate.The influence mechanism of the second phase(Mg_(2)Ca)on LDHs production was investigated.Increasing Ca content increased the amount of Mg_(2)Ca,decreasing the grain size and the corrosion rate of the alloys.The increased amount of the second phase particles and the grain refinement promoted the growth of LDHs,and thus led to the decreasing of corrosion rate of the Mg−xCa alloys with LDHs.A higher Mg_(2)Ca amount resulted in forming fluffy LDHs.Due to the dual effects of the second phase(Mg_(2)Ca)for LDHs growth and microgalvanic corrosion,LDHs/Mg−0.8Ca showed the lowest corrosion rate.
基金Financial supports from China Scholarship Council and Helmholtz Association of German Research Centers scholarship(No.2010821213) for Wang’s Ph D study in Helmholtz-Zentrum Geesthacht(HZG) are gratefully acknowledged
文摘Effects of Zn content (0, 0.5%, 1.5% and 4.5%) on the hot tearing characteristics of Mg?2%Y alloy were studied in aconstrained rod casting (CRC) apparatus attached with a load cell and data acquisition system. The experimental results indicate thatthe hot tearing susceptibility (HTS) is affected by the content of Zn. The Zn-free base alloy shows the lowest HTS. The HTS ofMg?xZn?2Y alloys increases with increasing Zn content, reaches the maximum at 1.5% Zn, and then decreases with further Znaddition. The high HTS observed in the alloy with 1.5% Zn is attributed to its high force release rate and large force drop duringsolidification. The hot cracks of casting are initiated and propagate along the dendritic or grain boundaries. The predictions of HTS ofMg?xZn?2Y alloys using ProCAST software are in good agreement with the results obtained by experimental measurements.
基金financially supported by the National Natural Science Foundation of China(Nos.52071036,U2037601)the Guangdong Major Project of Basic and Applied Basic Research,China(No.2020B0301030006)+1 种基金the Independent Research Project of State Key Laboratory of Mechanical Transmissions,China(Nos.SKLMT-ZZKT-2022Z01,SKLMT-ZZKT-2022M12)the Chongqing Science and Technology Commission,China(No.CSTB2022TIAD-KPX0021)。
文摘Edge cracking is one of the most serious problems in the rolling process of magnesium alloy sheets,which limits its application.In this work,the edge cracking behavior of different initial AZ31 alloy sheets,including as-cast(AC),as-rolled(AR)and as-extruded(AE),was systematically investigated and compared under the online heating rolling(O-LHR)process with a single-pass reduction of 50% at 250℃.The results show that both AC and AR sheets exhibit severe edge cracking behavior after the O-LHR.Among them,the AR sheet exhibits the severest edge cracking behavior on the rolling plane(RD-TD)and longitudinal section(RD-ND),which is attributed to the strong basal texture and extremely uneven microstructure with shear bands.While no visible edge crack appears in the AE rolled sheet,which is mainly related to the tilted texture and the more dynamic recrystallization during rolling process.Moreover,it is also found that the micro-cracks of the AC rolled sheet are mainly generated in the local fine-grained area and the twins where recrystallization occurs.In the AR rolled sheet,micro-cracks mainly develop inside the shear bands.Meanwhile,the micro-crack initiation mechanism of AC and AR rolled sheets was also discussed.
基金the National Magnetic Confinement Fusion Science Program(2013GB108002,2014GB112005)National Natural Science Foundation of China(11747042)+2 种基金Science and Technology Development Foundation of China Academy of Engineering Physics(xk201701)Sichuan Science and Technology Program(2019YJ0445)Project of State Key Laboratory of Environment-friendly Energy Materials,Southwest University of Science and Technology(17FKSY0105)。
文摘Separating high-purity hydrogen isotopes from their mixture still remains a huge challenge due to almost the identical physicochemical properties.Much importance has been attached to tune microstructure of porous materials,while heat management during hydrogen isotope separation tends to be ignored.Herein,a porous material 5 A molecular sieve(5 A)is mixed with graphene(GE)under ball grinding to enhance its thermal conductivity for hydrogen isotope separation.The thermal conductivity increases from 0.19 W m^(-1)K^(-1)of neat 5 A,0.75 W m^(-1)K^(-1)of 5 A/GE2(2 wt%GE)to 1.23 W m^(-1)K^(-1)of 5 A/GE8.In addition,introducing GE into 5 A promotes hydrogen adsorption and D_(2)/H_(2)adsorption ratio.5 A/GE2 shows the highest D_(2)adsorption capacity(5.40 mmol/g)and the largest D_(2)/H_(2)adsorption ratio(1.07)among the composites.It also displays a high efficiency of heat transfer that contributes to a low energy consumption due to the shortened cycle time during hydrogen isotope separation.This work offers new insights into material design for improved hydrogen isotope separation,which is greatly crucial to scientific and industrial applications,such as fuel self-sustaining in fusion reactors.
