In this paper,equal channel angular pressing and thermomechanical treatment was employed to improve the strength and electrical conductivity of an aging strengthened Cu-Ti-Cr-Mg alloy,and the microstructure and proper...In this paper,equal channel angular pressing and thermomechanical treatment was employed to improve the strength and electrical conductivity of an aging strengthened Cu-Ti-Cr-Mg alloy,and the microstructure and properties of the alloy were investigated in detail.The results showed that the samples deformed by the combination of cryogenic equal channel angular pressing(ECAP)and rolling had good comprehensive properties after aging at 400℃.The tensile strength of the peak-aged and over-aged samples was 1120 MPa and 940 MPa,with their corresponding electrical conductivity of 14.7%IACS and 22.1%IACS,respectively.ECAP and cryogenic rolling introduced high density dislocations,leading to the inhibition of the softening effects and refinement of the grains.After a long time aging at 400℃,the alloy exhibited ultra-high strength with obvious increasing electrical conductivity.The high strength was attributed to the synergistic effect of work hardening,grain refinement strengthening and precipitation strengthening.The precipitation of a large amount of Ti atoms from the matrix led to the high electrical conductivity of the over-aged sample.展开更多
A new processing method,equal channel angular pressing(ECAP)plus cold rolling(CR),was applied to producing ultra-fine grained FeCoV alloy.The microstructures of ultra-fine grained FeCoV alloy after ECAP,ECAP plus CR,a...A new processing method,equal channel angular pressing(ECAP)plus cold rolling(CR),was applied to producing ultra-fine grained FeCoV alloy.The microstructures of ultra-fine grained FeCoV alloy after ECAP,ECAP plus CR,and the effect of tempering treatment on the microstructure of FeCoV alloy produced by ECAP plus CR were investigated.The results show that an elongated substructure with a width of about 0.3μm is obtained after four-pass ECAP using Route A.Cold rolling after ECAP cannot change the morphologies of elongated substructure,and it results in higher fraction of high-angle boundaries and higher dislocation density compared with the identical ECAP without rolling.Subsequent tempering for 30 min at 853 K brings about many nano-phases precipitating at subgrain boundaries and insides the grains,and the size of precipitated phase is measured to be about 10 nm.Nano-phases grow up with increasing tempering temperature and equiaxed structure forms at 883 K.展开更多
The 1.0%Al2O3/Cu(mass fraction) composite was prepared by hot pressing(HP),then treated by rolling to get a full density. The microstructures and the micro area element distribution of the composite were analyzed by S...The 1.0%Al2O3/Cu(mass fraction) composite was prepared by hot pressing(HP),then treated by rolling to get a full density. The microstructures and the micro area element distribution of the composite were analyzed by SEM. The density,electric conductivity and tensile strength were also investigated. The experimental results show that the alumina particles are more dispersed and become smaller through a single-pass rolling. The pore existing in the composite is eliminated or closed under the rolling force. The relative density increases from 98.4% to 99.2%. The electric conductivity increases from 88.9%IACS to 91.2%IACS. The tensile strength is increased by 47% from 300 MPa to 440 MPa.展开更多
A commercial Al-Mg alloy was subjected to equal channel angular pressing of 4 passes with and without postrolling, and the effects of post-rolling on the deformation characteristics of the alloy at 723 K were examined...A commercial Al-Mg alloy was subjected to equal channel angular pressing of 4 passes with and without postrolling, and the effects of post-rolling on the deformation characteristics of the alloy at 723 K were examined. Post-rolling was found to influence the deformation behavior significantly. The deformation behavior of the alloy processed only by equal channel angular pressing was characterized by (a) localized deformation indicated by severe surface prominence and depression, (b) the strain rate sensitivity of 0.33, and (c) moderate high strain rate superplastic elongations. By contrast, that of the alloy processed by equal channel angular pressing and post-rolling (70 % thickness reduction) was manifested by (a) uniform deformation associated with grain boundary sliding throughout the sample, (b) a sigmoidal behavior showing the strain rate sensitivity of 0.45 at the intermediate strain rates in the logarithmic stress-strain rate curve, and (c) very large high strain rate superplastic elongations.展开更多
基金Project(U2202255)supported by the National Natural Science Foundation of ChinaProject(2024JJ2076)supported by the Hunan Provincial Natural Science Foundation of ChinaProject(2023Z092)supported by the Key Technology Research Program of Ningbo,China。
文摘In this paper,equal channel angular pressing and thermomechanical treatment was employed to improve the strength and electrical conductivity of an aging strengthened Cu-Ti-Cr-Mg alloy,and the microstructure and properties of the alloy were investigated in detail.The results showed that the samples deformed by the combination of cryogenic equal channel angular pressing(ECAP)and rolling had good comprehensive properties after aging at 400℃.The tensile strength of the peak-aged and over-aged samples was 1120 MPa and 940 MPa,with their corresponding electrical conductivity of 14.7%IACS and 22.1%IACS,respectively.ECAP and cryogenic rolling introduced high density dislocations,leading to the inhibition of the softening effects and refinement of the grains.After a long time aging at 400℃,the alloy exhibited ultra-high strength with obvious increasing electrical conductivity.The high strength was attributed to the synergistic effect of work hardening,grain refinement strengthening and precipitation strengthening.The precipitation of a large amount of Ti atoms from the matrix led to the high electrical conductivity of the over-aged sample.
基金Project(50675133)supported by the National Natural Science Foundation of ChinaProject(2006CB705401)supported by the National Basic Research Program of China
文摘A new processing method,equal channel angular pressing(ECAP)plus cold rolling(CR),was applied to producing ultra-fine grained FeCoV alloy.The microstructures of ultra-fine grained FeCoV alloy after ECAP,ECAP plus CR,and the effect of tempering treatment on the microstructure of FeCoV alloy produced by ECAP plus CR were investigated.The results show that an elongated substructure with a width of about 0.3μm is obtained after four-pass ECAP using Route A.Cold rolling after ECAP cannot change the morphologies of elongated substructure,and it results in higher fraction of high-angle boundaries and higher dislocation density compared with the identical ECAP without rolling.Subsequent tempering for 30 min at 853 K brings about many nano-phases precipitating at subgrain boundaries and insides the grains,and the size of precipitated phase is measured to be about 10 nm.Nano-phases grow up with increasing tempering temperature and equiaxed structure forms at 883 K.
基金Project (50174007) supported by the National Natural Science Foundation of China
文摘The 1.0%Al2O3/Cu(mass fraction) composite was prepared by hot pressing(HP),then treated by rolling to get a full density. The microstructures and the micro area element distribution of the composite were analyzed by SEM. The density,electric conductivity and tensile strength were also investigated. The experimental results show that the alumina particles are more dispersed and become smaller through a single-pass rolling. The pore existing in the composite is eliminated or closed under the rolling force. The relative density increases from 98.4% to 99.2%. The electric conductivity increases from 88.9%IACS to 91.2%IACS. The tensile strength is increased by 47% from 300 MPa to 440 MPa.
文摘A commercial Al-Mg alloy was subjected to equal channel angular pressing of 4 passes with and without postrolling, and the effects of post-rolling on the deformation characteristics of the alloy at 723 K were examined. Post-rolling was found to influence the deformation behavior significantly. The deformation behavior of the alloy processed only by equal channel angular pressing was characterized by (a) localized deformation indicated by severe surface prominence and depression, (b) the strain rate sensitivity of 0.33, and (c) moderate high strain rate superplastic elongations. By contrast, that of the alloy processed by equal channel angular pressing and post-rolling (70 % thickness reduction) was manifested by (a) uniform deformation associated with grain boundary sliding throughout the sample, (b) a sigmoidal behavior showing the strain rate sensitivity of 0.45 at the intermediate strain rates in the logarithmic stress-strain rate curve, and (c) very large high strain rate superplastic elongations.
