The deformation of Cu–20 wt.%Fe alloy wires leads to a significant improvement in mechanical properties and a decrease in electrical conductivity.Simultaneous improvements in strength and conductivity were achieved b...The deformation of Cu–20 wt.%Fe alloy wires leads to a significant improvement in mechanical properties and a decrease in electrical conductivity.Simultaneous improvements in strength and conductivity were achieved by intermediate annealing of drawn Cu–20 wt.%Fe wires.As the annealing temperature increased,the strength of Cu–20 wt.%Fe alloy wire decreased monotonically,but the electrical conductivity first increased and then decreased,reaching its peak value after annealing at 500℃.The decrease in strength is related to dislocation recovery and static recrystallization of Cu and Fe phases,and the increase in electrical conductivity mainly results from the aging precipitation of solid solution Fe.After annealing at 500℃,there was no obvious recrystallization of Cu phase,and many of the nano-Fe particles precipitated from Cu matrix.An annealing temperature of 600℃ induced the recrystallization of Cu matrix and an increase in Fe solid solubility,resulting in a decrease in strength and electrical conductivity.Subsequently,the wires annealed at 500℃ were drawn to 2 mm.Compared with those of the continuously drawn Cu–20 wt.%Fe alloy wires,the deformation ability,strength,and electrical conductivity of Cu–20 wt.%Fe alloy wires subjected to intermediate annealing treatment are significantly greater.This is mainly related to the sufficient precipitation of Fe in Cu matrix and the strengthening of refined Fe fibers parallel to the drawing direction.展开更多
Increasing density is one of the important factors for producing high quality powder metallurgy （PM） parts, which has beneficial effect on mechanical properties. One of the common techniques for achieving this goal ...Increasing density is one of the important factors for producing high quality powder metallurgy （PM） parts, which has beneficial effect on mechanical properties. One of the common techniques for achieving this goal is double compacting, which seems to be a potentially attractive method in PM route, also for Cr-Mo alloyed-steels. The objective of this research was to investigate the effect of first compacting pressure and intermediate annealing temperature on attaining higher densities and minimum interconnected porosity for Cr-Mo pre-alloyed steel. The effect of mentioned parameters was studied by measuring density, transverse rupture strength and macrohardness of repressed samples. The results show that for each first compacting pressure, the density range of repressed samples increases with the increasing annealing temperature up to a certain limit, due to C dissolution which causes free porosity and further densifieation. Annealing temperatures higher than optimum one should be avoided, since too much carbon dissolution results in harder and less deformable compacts. On the other hand, with regard to repressed density and other resulted properties, the amount of first compacting pressure offers considerable advantage in obtaining higher level of density and consequently improved mechanical properties.展开更多
The effects of the inter-annealing process on the microstructure,plane stress fracture toughness,and tensile properties of an AA7075 cladding sheet were investigated using optical microscopy,scanning electron microsco...The effects of the inter-annealing process on the microstructure,plane stress fracture toughness,and tensile properties of an AA7075 cladding sheet were investigated using optical microscopy,scanning electron microscopy,electron backscattered diffraction,transmission electron microscopy,and mechanical property tests.The results indicate that the plane stress fracture toughness of AA7075-T6 cladding sheet can be greatly improved.The plane stress fracture toughness for the longitudinal-transverse(L-T)and transverse-longitudinal(T-L)directions were 117.7 and 94.8 MPa·m^(1/2),respectively,after intermediate annealing at 380°C.This represents an increase of 23.9 MPa·m^(1/2)in the L-T direction and 22.6 MPa·m^(1/2) in the T-L direction compared with the AA7075-T6 cladding sheet without intermediate annealing.Moreover,the tensile strength remains similar under different conditions.Microstructure analysis indicates that intermediate annealing before heat treatment can result in long sub-grains,few recrystallized grain boundaries,and small size precipitates in AA7075-T6 cladding sheets.展开更多
The effects of drawing strain during intermediate annealing on the microstructure and properties of Cu-20 wt%Fe alloy wires while maintaining constant total deformation were investigated.Intermediate annealing effecti...The effects of drawing strain during intermediate annealing on the microstructure and properties of Cu-20 wt%Fe alloy wires while maintaining constant total deformation were investigated.Intermediate annealing effectively removes work hardening in both the Cu matrix and Fe fibers,restoring their plastic deformation capacity and preserving fiber continuity during subsequent redrawing.The process also refines the Fe phase,leading to a more uniform size distribution and straighter,better-aligned Cu/Fe phase interfaces,thereby enhancing the comprehensive properties of the alloy.The magnitude of drawing strain during intermediate annealing plays a critical role in balancing the mechanical strength and electrical conductivity of redrawn wires.A lower initial drawing strain requires greater redrawing strain,leading to excessive hardening of the Fe fibers,which negatively impacts the electrical conductivity and tensile plasticity.Conversely,a higher initial drawing strain can result in insufficient work hardening during the redrawing deformation process,yielding minimal strength improvements.Among the tested alloys,H/3.5 wires show a slight reduction in strength and hardness compared to W and H/4.5 wires but exhibit a significant increase in tensile elongation and electrical conductivity.The tensile strength was 755 MPa,and the electrical conductivity was 47%international-annealed copper standard(IACS).The optimal performance is attributed to the formation of a high-density,ultrafine Fe fiber structure-aligned parallel to the drawing direction,which is achieved through a suitable combination of the drawing process and intermediate annealing.展开更多
基金support provided by National Natural Science Foundation of China(Nos.52405364 and 52171110)Jiangsu Funding Program for Excellent Postdoctoral Talent+3 种基金JITRI Advanced Materials R&D Co.Ltdsupport by European Union Horizon 2020 Research and Innovation Program(857470)European Regional Development Fund via the Foundation for Polish Science International Research Agenda PLUS program(MAB PLUS/2018/8)The publication was created within the framework of the project of the Minister of Science and Higher Education,Support for the Activities of Centres of Excellence established in Poland under Horizon 2020,under contract No.MEiN/2023/DIR/3795.
文摘The deformation of Cu–20 wt.%Fe alloy wires leads to a significant improvement in mechanical properties and a decrease in electrical conductivity.Simultaneous improvements in strength and conductivity were achieved by intermediate annealing of drawn Cu–20 wt.%Fe wires.As the annealing temperature increased,the strength of Cu–20 wt.%Fe alloy wire decreased monotonically,but the electrical conductivity first increased and then decreased,reaching its peak value after annealing at 500℃.The decrease in strength is related to dislocation recovery and static recrystallization of Cu and Fe phases,and the increase in electrical conductivity mainly results from the aging precipitation of solid solution Fe.After annealing at 500℃,there was no obvious recrystallization of Cu phase,and many of the nano-Fe particles precipitated from Cu matrix.An annealing temperature of 600℃ induced the recrystallization of Cu matrix and an increase in Fe solid solubility,resulting in a decrease in strength and electrical conductivity.Subsequently,the wires annealed at 500℃ were drawn to 2 mm.Compared with those of the continuously drawn Cu–20 wt.%Fe alloy wires,the deformation ability,strength,and electrical conductivity of Cu–20 wt.%Fe alloy wires subjected to intermediate annealing treatment are significantly greater.This is mainly related to the sufficient precipitation of Fe in Cu matrix and the strengthening of refined Fe fibers parallel to the drawing direction.
文摘Increasing density is one of the important factors for producing high quality powder metallurgy （PM） parts, which has beneficial effect on mechanical properties. One of the common techniques for achieving this goal is double compacting, which seems to be a potentially attractive method in PM route, also for Cr-Mo alloyed-steels. The objective of this research was to investigate the effect of first compacting pressure and intermediate annealing temperature on attaining higher densities and minimum interconnected porosity for Cr-Mo pre-alloyed steel. The effect of mentioned parameters was studied by measuring density, transverse rupture strength and macrohardness of repressed samples. The results show that for each first compacting pressure, the density range of repressed samples increases with the increasing annealing temperature up to a certain limit, due to C dissolution which causes free porosity and further densifieation. Annealing temperatures higher than optimum one should be avoided, since too much carbon dissolution results in harder and less deformable compacts. On the other hand, with regard to repressed density and other resulted properties, the amount of first compacting pressure offers considerable advantage in obtaining higher level of density and consequently improved mechanical properties.
基金the National Key R&D Program of China(Nos.2023YFB3710401,2022YFB3504401)the National Natural Science Foundation of China(Nos.52271094,U1708251)+1 种基金the Key Research and Development Program of Liaoning,China(No.2020JH2/10700003)Qingyuan City Science and Technology Plan Project(No.2023YFJH003),China.
文摘The effects of the inter-annealing process on the microstructure,plane stress fracture toughness,and tensile properties of an AA7075 cladding sheet were investigated using optical microscopy,scanning electron microscopy,electron backscattered diffraction,transmission electron microscopy,and mechanical property tests.The results indicate that the plane stress fracture toughness of AA7075-T6 cladding sheet can be greatly improved.The plane stress fracture toughness for the longitudinal-transverse(L-T)and transverse-longitudinal(T-L)directions were 117.7 and 94.8 MPa·m^(1/2),respectively,after intermediate annealing at 380°C.This represents an increase of 23.9 MPa·m^(1/2)in the L-T direction and 22.6 MPa·m^(1/2) in the T-L direction compared with the AA7075-T6 cladding sheet without intermediate annealing.Moreover,the tensile strength remains similar under different conditions.Microstructure analysis indicates that intermediate annealing before heat treatment can result in long sub-grains,few recrystallized grain boundaries,and small size precipitates in AA7075-T6 cladding sheets.
基金support provided by the National Natural Science Foundation of China(Nos.52405364,and 52171110)the Jiangsu Funding Program for Excellent Postdoctoral Talent.W.Huo acknowledges the support from the European Union Horizon 2020 Research and Innovation Program(No.857470)+1 种基金from the European Regional Development Fund via the Foundation for Polish Science International Research Agenda PLUS Program(No.MAB PLUS/2018/8)The publication was partly created within the framework of the project of the Minister of Science and Higher Education"Support for the activities of Centers of Excellence established in Poland under Horizon 2020"(No.MEiN/2023/DIR/3795).
文摘The effects of drawing strain during intermediate annealing on the microstructure and properties of Cu-20 wt%Fe alloy wires while maintaining constant total deformation were investigated.Intermediate annealing effectively removes work hardening in both the Cu matrix and Fe fibers,restoring their plastic deformation capacity and preserving fiber continuity during subsequent redrawing.The process also refines the Fe phase,leading to a more uniform size distribution and straighter,better-aligned Cu/Fe phase interfaces,thereby enhancing the comprehensive properties of the alloy.The magnitude of drawing strain during intermediate annealing plays a critical role in balancing the mechanical strength and electrical conductivity of redrawn wires.A lower initial drawing strain requires greater redrawing strain,leading to excessive hardening of the Fe fibers,which negatively impacts the electrical conductivity and tensile plasticity.Conversely,a higher initial drawing strain can result in insufficient work hardening during the redrawing deformation process,yielding minimal strength improvements.Among the tested alloys,H/3.5 wires show a slight reduction in strength and hardness compared to W and H/4.5 wires but exhibit a significant increase in tensile elongation and electrical conductivity.The tensile strength was 755 MPa,and the electrical conductivity was 47%international-annealed copper standard(IACS).The optimal performance is attributed to the formation of a high-density,ultrafine Fe fiber structure-aligned parallel to the drawing direction,which is achieved through a suitable combination of the drawing process and intermediate annealing.
