Effect Of ECAP/Bc Route Deformation And Heat Treatment On Microstructure And Properties Of Cu-Cr-x Alloy

Copper and copper alloys have good comprehensive performance and are widely used in information,transportation,electric power and other industries.With the development of the national economy,the related fields put forward higher requirements for the performance of copper alloys.Cu-Cr alloys are highly conductive.The material has a wide range of engineering applications,but the relatively low tensile strength severely limits the application of the alloy in the cutting-edge field.Aiming at this problem,this thesis takes Cu-Cr-x(Cr,Zr)alloys as the research object,and uses ECAP technology to multi-pass the alloy with Bc path,and the deformation alloy has different aging at 350 °C and 400 °C.Time(1h,2h,4h,6h,8h);Through OM,XRD,SEM,EDS,EBSD and other techniques,the microstructure evolution and orientation change of the alloy during deformation and aging were characterized.The mechanical properties and electrical conductivity of the alloy were tested.The influencing factors of the alloy properties were analyzed.The evolution of texture and its response to performance were investigated.The results show that after the ECAP deformation of Cu-Cr-Si/Zr alloy,the original grains are elongated,and the cross-cut shear bands are formed in 2 passes,and the fiber structure along the extrusion direction is transformed in 8 passes.The crystal grains are broken and transformed into fine equiaxed crystals.After deformation,the strength of the alloy is greatly improved,and the electrical conductivity decreases slightly.After 5 passes,the strength of Cu-Cr-Si alloy reaches574.6MPa,and Cu-Cr-Zr reaches 618.6MPa,which is 44.5% and43.9%higher than the original state.The conductivity of the alloy after 8passes reached 72.52% IACS and 60% IACS,respectively.After aging of Cu-Cr-Si/Zr alloy,a large number of fine granular precipitates distributed along the grain boundary are precipitated in the alloy structure.With the extension of aging time,the precipitates gradually grow and appear irregular,and the precipitation phases of the two alloys are mainly Cr phase,Cr-Si phase and Zr-rich phase.Cu-Cr-Si alloy has good comprehensive performance after aging at 350 °C for 4h,tensile strength reaches 488.72 MPa,electrical conductivity reaches 83.43% IACS;Cu-Cr-Zr alloy ECAP deforms after 400 °C aging It exhibits good overall performance,tensile strength up to 631.74 MPa and conductivity up to 75% IACS.There are mainly three kinds of textures on the cross section of ?2=0°after deformation and aging of Cu-Cr-Si alloy,{110}<001> Goss texture in1 pass,weaker in 2 passes and 4 passes.{001}<100>Cube texture,the weaker {001}<110>Rotated-cube texture in 8 passes;on the spatial section of ?2=45°,there are strong 2 and 4 passes { 111}<112> texture,{111}<110>and {111}<112> textures existed in 8 passes,the strength is reduced,and{111}<110> texture can improve the conductivity of fcc crystal materials.