In recent years magnesium alloys have been studied intensively with a view to their potential use in bioresorbable medical implants.In the present work the microstructure and the corrosion properties of a new bioresor...In recent years magnesium alloys have been studied intensively with a view to their potential use in bioresorbable medical implants.In the present work the microstructure and the corrosion properties of a new bioresorbable Mg-4 wt%Ga-4 wt%Zn alloy and its variants with low Ca,Nd or Y additions were investigated.These alloys are of interest due to the efficacy of gallium as an element inhibiting bone resorption,osteoporosis,Paget's disease,and other illnesses.A severe plastic deformation technique of equal channel angular pressing(ECAP)was shown to provide the alloys with favorable mechanical properties.In addition,a desirable low rate of degradation in a simulated body fluid(Hanks'solution)was achieved.展开更多
Magnesium and its alloys are the most investigated materials for solid-state hydrogen storage in the form of metal hydrides,but there are still unresolved problems with the kinetics and thermodynamics of hydrogenation...Magnesium and its alloys are the most investigated materials for solid-state hydrogen storage in the form of metal hydrides,but there are still unresolved problems with the kinetics and thermodynamics of hydrogenation and dehydrogenation of this group of materials.Severe plastic deformation(SPD)methods,such as equal-channel angular pressing(ECAP),high-pressure torsion(HPT),intensive rolling,and fast forging,have been widely used to enhance the activation,air resistance,and hydrogenation/dehydrogenation kinetics of Mg-based hydrogen storage materials by introducing ultrafine/nanoscale grains and crystal lattice defects.These severely deformed materials,particularly in the presence of alloying additives or second-phase nanoparticles,can show not only fast hydrogen absorption/desorption kinetics but also good cycling stability.It was shown that some materials that are apparently inert to hydrogen can absorb hydrogen after SPD processing.Moreover,the SPD methods were effectively used for hydrogen binding-energy engineering and synthesizing new magnesium alloys with low thermodynamic stability for reversible low/room-temperature hydrogen storage,such as nanoglasses,high-entropy alloys,and metastable phases including the high-pressureγ-MgH2 polymorph.This work reviews recent advances in the development of Mg-based hydrogen storage materials by SPD processing and discusses their potential in future applications.展开更多
We review the principle of topological interlocking and analyze the properties of the mortarless structures whose design is based on this principle.We concentrate on structures built of osteomorphic blocks-the blocks ...We review the principle of topological interlocking and analyze the properties of the mortarless structures whose design is based on this principle.We concentrate on structures built of osteomorphic blocks-the blocks possessing specially engineered contact surfaces allowing assembling various 2D and 3D structures.These structures are easy to build and can be made demountable.They are flexible,resistant to macroscopic fractures and tolerant to missing blocks.The blocks are kept in place without keys or connectors that are the weakest elements of the conventional interlocking structures.The overall structural integrity of these structures depends on the force imposed by peripheral constraint.The peripheral constraint can be provided in various ways:by an external flame or features of site topography,intemal prestressed cables/tendons,or self-weight and is a necessary auxiliary element of the structure.The constraining force also determines the degree of delamination developing between the blocks due to bending and thus controls the overall flexibility of the structure thus becoming a new design parameter.展开更多
基金The authors gratefully acknowledge financial support from the Ministry of Science and Higher Education of the Russian Federation under the Increasing Competitiveness Program of NUST"MISiS"(No.K2-2019-008)implemented according to the governmental decree N 211 dated 16 March 2013.
文摘In recent years magnesium alloys have been studied intensively with a view to their potential use in bioresorbable medical implants.In the present work the microstructure and the corrosion properties of a new bioresorbable Mg-4 wt%Ga-4 wt%Zn alloy and its variants with low Ca,Nd or Y additions were investigated.These alloys are of interest due to the efficacy of gallium as an element inhibiting bone resorption,osteoporosis,Paget's disease,and other illnesses.A severe plastic deformation technique of equal channel angular pressing(ECAP)was shown to provide the alloys with favorable mechanical properties.In addition,a desirable low rate of degradation in a simulated body fluid(Hanks'solution)was achieved.
基金supported in part by the Light Metals Educational Foundation of Japan,and in part by the MEXT,Japan through Grants-in-Aid for Scientific Research on Innovative Areas(Nos.JP19H05176&JP21H00150)the Challenging Research Exploratory(Grant No.JP22K18737)+6 种基金W.J.Botta is grateful to the Brazilian agencies FAPESP(Grant No.2013/05987-8)CNPq(Grant Nos.421181-2018-4 and 307397-2019-0)the financial support and to the Laboratory of Structural Characterization(LCE-DEMa-UFSCar)for general electron microscopy facilities.R.Floriano thanks for the financial support from FAPESP(Grant No.2022/01351-0)support from the French State through the ANR-21-CE08-0034-01 project as well as the program“Investment in the future”operated by the National Research Agency(ANR)referenced under No.ANR-11-LABX-0008-01(Labex DAMAS)support from the National Natural Science Foundation of China(Grant No.52171205)support from the National Natural Science Foundation of China(Grant No.52071157).
文摘Magnesium and its alloys are the most investigated materials for solid-state hydrogen storage in the form of metal hydrides,but there are still unresolved problems with the kinetics and thermodynamics of hydrogenation and dehydrogenation of this group of materials.Severe plastic deformation(SPD)methods,such as equal-channel angular pressing(ECAP),high-pressure torsion(HPT),intensive rolling,and fast forging,have been widely used to enhance the activation,air resistance,and hydrogenation/dehydrogenation kinetics of Mg-based hydrogen storage materials by introducing ultrafine/nanoscale grains and crystal lattice defects.These severely deformed materials,particularly in the presence of alloying additives or second-phase nanoparticles,can show not only fast hydrogen absorption/desorption kinetics but also good cycling stability.It was shown that some materials that are apparently inert to hydrogen can absorb hydrogen after SPD processing.Moreover,the SPD methods were effectively used for hydrogen binding-energy engineering and synthesizing new magnesium alloys with low thermodynamic stability for reversible low/room-temperature hydrogen storage,such as nanoglasses,high-entropy alloys,and metastable phases including the high-pressureγ-MgH2 polymorph.This work reviews recent advances in the development of Mg-based hydrogen storage materials by SPD processing and discusses their potential in future applications.
基金This research was supported through the ARC Discovery Grant DP120102434AVD and EP also acknowledge support through the ARC Discovery grant DP0988449.
文摘We review the principle of topological interlocking and analyze the properties of the mortarless structures whose design is based on this principle.We concentrate on structures built of osteomorphic blocks-the blocks possessing specially engineered contact surfaces allowing assembling various 2D and 3D structures.These structures are easy to build and can be made demountable.They are flexible,resistant to macroscopic fractures and tolerant to missing blocks.The blocks are kept in place without keys or connectors that are the weakest elements of the conventional interlocking structures.The overall structural integrity of these structures depends on the force imposed by peripheral constraint.The peripheral constraint can be provided in various ways:by an external flame or features of site topography,intemal prestressed cables/tendons,or self-weight and is a necessary auxiliary element of the structure.The constraining force also determines the degree of delamination developing between the blocks due to bending and thus controls the overall flexibility of the structure thus becoming a new design parameter.
