The poor mechanical properties of pure zinc(Zn)restrain its applications in orthopedics,which requires high loading capacity.Alloying with lithium(Li)element can enhance strength,however,the work-hardening rate is imp...The poor mechanical properties of pure zinc(Zn)restrain its applications in orthopedics,which requires high loading capacity.Alloying with lithium(Li)element can enhance strength,however,the work-hardening rate is impaired with increased Li content.Here,introducing scandium(Sc)into a low Li-containing Zn-0.1Li alloy could effectively refine its microstructure,reducing the average grain size from 10 to 4μm.The refinement in microstructure led to a significant improvement in tensile strength,im-proving from 257 MPa of Zn-0.1Li to 341 MPa of Zn-0.1Li-0.1Sc,meanwhile,the work-hardening rate remained positive during the whole plastic deformation stage.The addition of Sc-impaired elongation is due to numerous microcracks formed at the Zn/ScZn_(12)interfaces,as well as in the large-sized ScZn_(12)particles.Corrosion tests revealed an accelerated corrosion rate due to the galvanic effect between the Zn matrix and ScZn_(12)phase.Even so,the Zn-0.1Li-1.0Sc alloy still exhibited superior biocompatibility with rat/mouse mesenchymal stem cells and close osteogenesis capacity to the original Zn-0.1Li alloy.These findings demonstrated that the addition of Sc in low Li-containing alloys could improve mechanical strength without sacrificing the work-hardening rate and biocompatibility.展开更多
To date,nanostructuring through plastic deformation has rarely been reported in biodegradable zinc(Zn)based alloys that have great potential in load-bearing conditions.Here,typical high-strength Zn-Li-based alloys wer...To date,nanostructuring through plastic deformation has rarely been reported in biodegradable zinc(Zn)based alloys that have great potential in load-bearing conditions.Here,typical high-strength Zn-Li-based alloys were subjected to SPD processes,including equal channel angular pressing(ECAP)and high-pressure torsion(HPT),to achieve nanostructured microstructures.The effects of SPD on the microstructures,mechanical properties,and corrosion behaviors were generally investigated.The two SPD routes resulted in totally different microstructures.ECAPed samples processed at 150℃ exhibited a complicated multilevel structure(nm toμm)with mixed Zn equiaxed grains and lamellar-like eutectoid regions(Zn+α-LiZn_(4)),and HPTed ones(25℃)possessed a fully dynamically recrystallized(DRXed)microstructure with an average grain size below 0.4μm.The tensile strength of the SPD samples could reach 500 MPa.Meanwhile,HPTed samples exhibited extraordinary fracture elongations higher than 100%,because of a different grain boundary sliding deformation mechanism.HPTed samples and ECAPed samples displayed different corrosion patterns,and the former exhibited a much higher corrosion rate in Hank's solution,possibly due to the accelerated corrosion at grain boundaries.In summary,SPD is an efficient way to refine the microstructure of biodegradable Zn-based alloys,possibly improving their performances and clinical applications.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.U22A20121 and 52101283)the Suzhou Science and Technology Project(Grant No SJC2023005)+3 种基金the Science and Technology Planning Project of Guangzhou(Grant No 202102010008)the High-Level Hospital Construction Project(Grant No KJ012019520)the Beijing Mu-nicipal Health Commission(BMHC-2021-6,BJRITO-RDP-2024)the Beijing Municipal Public Welfare Development and Reform Pilot Project for Medical Research Institutes(Nos.JYY2023-11 and JYY2023-8).
文摘The poor mechanical properties of pure zinc(Zn)restrain its applications in orthopedics,which requires high loading capacity.Alloying with lithium(Li)element can enhance strength,however,the work-hardening rate is impaired with increased Li content.Here,introducing scandium(Sc)into a low Li-containing Zn-0.1Li alloy could effectively refine its microstructure,reducing the average grain size from 10 to 4μm.The refinement in microstructure led to a significant improvement in tensile strength,im-proving from 257 MPa of Zn-0.1Li to 341 MPa of Zn-0.1Li-0.1Sc,meanwhile,the work-hardening rate remained positive during the whole plastic deformation stage.The addition of Sc-impaired elongation is due to numerous microcracks formed at the Zn/ScZn_(12)interfaces,as well as in the large-sized ScZn_(12)particles.Corrosion tests revealed an accelerated corrosion rate due to the galvanic effect between the Zn matrix and ScZn_(12)phase.Even so,the Zn-0.1Li-1.0Sc alloy still exhibited superior biocompatibility with rat/mouse mesenchymal stem cells and close osteogenesis capacity to the original Zn-0.1Li alloy.These findings demonstrated that the addition of Sc in low Li-containing alloys could improve mechanical strength without sacrificing the work-hardening rate and biocompatibility.
基金supported by the National Natural Science Foundation of China(Nos.U22A20121,52101283 and 52271243)the NSFC-RGC Joint Research Scheme(No.52361165619)+3 种基金The NSFC-RFBR Joint Research Scheme(No.82361138575)the Science and Technology Planning Project of Guangzhou(No.202201011454)the National Key R&D Program of China(Nos.2021YFC2400700 and 2021YFC2400704)the High-level Hospital Construction Project(No.KJ012019520).
文摘To date,nanostructuring through plastic deformation has rarely been reported in biodegradable zinc(Zn)based alloys that have great potential in load-bearing conditions.Here,typical high-strength Zn-Li-based alloys were subjected to SPD processes,including equal channel angular pressing(ECAP)and high-pressure torsion(HPT),to achieve nanostructured microstructures.The effects of SPD on the microstructures,mechanical properties,and corrosion behaviors were generally investigated.The two SPD routes resulted in totally different microstructures.ECAPed samples processed at 150℃ exhibited a complicated multilevel structure(nm toμm)with mixed Zn equiaxed grains and lamellar-like eutectoid regions(Zn+α-LiZn_(4)),and HPTed ones(25℃)possessed a fully dynamically recrystallized(DRXed)microstructure with an average grain size below 0.4μm.The tensile strength of the SPD samples could reach 500 MPa.Meanwhile,HPTed samples exhibited extraordinary fracture elongations higher than 100%,because of a different grain boundary sliding deformation mechanism.HPTed samples and ECAPed samples displayed different corrosion patterns,and the former exhibited a much higher corrosion rate in Hank's solution,possibly due to the accelerated corrosion at grain boundaries.In summary,SPD is an efficient way to refine the microstructure of biodegradable Zn-based alloys,possibly improving their performances and clinical applications.
