Microstructure Evolution And Performance Control Of Low Temperature ECAP And Heat Treatment Cu0.4Cr0.3Zr Alloy

According to new infrastructure construction projects,the development of UHV power transmission,intercity high-speed rail and rail transit has become the primary goal.As the copper metal with the best electrical conductivity,the strength is insufficient,and alloying has caused the conductivity of pure copper to decrease seriously.In order to explore the match between strength and conductivity,this topic uses Cu0.4Cr0.3Zr alloy as the research object,using room temperature and liquid nitrogen environment ECAP is performed on different paths,and the deformed alloy is aged at 450°C for different lengths of time.Using OM,XRD,EDS,SEM,EBSD and microhardness measurement techniques to characterize the properties of the alloy in different states,and analyze the effects of different factors on the properties of the alloy.The results show that ECAP at different temperatures can refine the internal grains of the material.After 4 passes of low-temperature extrusion,the strength of the route Bc is 492.80 MPa and the conductivity is 42.2%IACS.The strength of the route Bc after4 passes at room temperature was 380.5MPa and the conductivity was 43%IACS.The conductivity is basically the same and the strength is increased by 77.4% and 37%respectively compared with the original state.The results show that aging has different effects on alloys with different deformation processes.After the alloy is extruded through the Bc path at room temperature for 4 passes and aging at 450°C for 3 hours,the strength reaches 538.6MPa and the conductivity is 75%IACS,After the alloy is extruded through the Bc path at low temperature for 4 passes and aging at 450°C for 3 hours,the strength reaches585.1MPa and the conductivity is 75%IACS.The electrical conductivity is basically the same,and the strength is respectively increased by 93.89% and 110.6% compared to the original state.The deformation route affects the strength of the alloy.After 4passes of low-temperature extrusion,the strength and conductivity are respectively,route A: 514 MPa,42.7% IACS;route Bc: 492.8MPa,42.2% IACS;route C: 510.6MPa,42.2% IACS.After aging at 450°C for 1h,route A: 599.2MPa,74.97% IACS;route Bc:585.1MPa,75.01% IACS;route C: 539.7MPa,74.9%IACS.The stacking fault energy of the alloy is reduced in a low temperature.The original dislocation segmentation mechanism of the Cu0.4Cr0.3Zr alloy in deformation has become a twin deformation mechanism,which is more likely to produce ultra-fine grains.During aging,the conductivity increases with the recovery of defects such as internal vacancies and internal stress,and at the same time,the strength is greatly improved by pinning the grain boundary after the solid solution desolves.The(111)crystal plane diffraction intensity of Cu0.4Cr0.3Zr alloy under different processes is the highest,but its value decreases with the increase of the deformation pass.The diffraction intensity of the crystal plane of the cold extrusion deformation is significantly higher than that of the room temperature extrusion.After multiple passes of deformation The main texture is {111}<112>.