Study On SPD Deformation Microstructure And Properties Of Cu0.8Cr0.6Zr Alloy At Room Temperature

Copper and copper alloy materials are widely used in high-tech fields such as microelectronic components,integrated circuits,and communications due to their excellent electrical conductivity,ductility,wear resistance and corrosion resistance.With the rapid development of science and technology,the requirements for its performance are increasingly strict,especially for high strength and high conductivity.However,high strength and high conductivity in copper alloys are contradictory and difficult to achieve at the same time,which severely limits the large-scale application of copper alloy materials.To solve this problem,this study used different routes of room temperature equal channel angular pressing(ECAP)and aging treatment to treat the Cu0.8Cr0.6Zr alloy.Using OM,SEM,EDS,XRD and EBSD methods to observe the microstructure evolution of the material,characterize the evolution of the macro and micro orientation of the crystal grains,and test the mechanical and electrical properties of the material.The influence of the microstructure evolution on the material properties of the Cu0.8Cr0.6Zr alloy after different process treatments was systematically studied,and the correlation effect between the texture evolution and the material properties was determined,and the best preparation process of the Cu0.8Cr0.6Zr alloy was determined,aiming to improve the mechanical properties and conductivity of the alloy at the same time.The results show that after the ECAP deformation,the grains continue to be refined under low strain.Under high strain,the grains are continuously broken and the size tends to be uniform.Finally,a fibrous structure along the extrusion direction is formed.The strength and hardness of the material after deformation are greatly improved.After ECAP deformation by route A/C,the tensile strength and hardness of the alloy increased from 347.90 MPa and 104.25 HV to 553.55 MPa,147.30 HV and549.83 MPa,156.90 HV,respectively.The fracture mode of the alloy after deformation changes from toughness?brittle fracture.During deformation,the main slip plane is(111)crystal plane,as the amount of deformation increases,the secondary slip plane is activated,alternating between the(200)crystal plane and the(220)crystal plane.At high passes,the cross-slip phenomenon occurs.After aging treatment,the second phase particles(mainly Cr phase and Cu₅Zr)dispersed and precipitated inside the crystal are the main reason for the improvement of alloy strength and electrical conductivity.After aging,the fracture mode of the alloy changes from ductile fracture?brittle fracture?ductile fracture,and the continuous growth of the precipitated phase is one of the reasons for the material fracture.Aging at 450°C for 4 hours is the best aging process for Cu0.8Cr0.6Zr alloys.After the alloy deformation by route A/C and the best aging process,the tensile strength,hardness and electrical conductivity can reach 562.59 MPa,168.23 HV,81.5%IACS and 590.11 MPa,174.95 HV,79.5%IACS,respectively.Cu0.8Cr0.6Zr alloy after deformation and aging treatment,as the number of deformation passes increases,the grain orientation becomes more disordered,and the proportion of high-angle grain boundaries(HAGBs)continues to increase,and eventually tending to be homogenized.The preferred orientation of the texture is also constantly changing.After the first 2 passes of deformation and aging treatment,the main textures are{110}<112>brass texture and{001}<110>shear texture,and also formed{111}<110>texture which is beneficial to the conductivity of the material.After 4 passes of deformation and aging,the texture gradually tends to be uniform,and leaving a strong{111}<001>Goss texture and{111}<112>texture in the end.After deformation and aging treatment,the dislocation density of the two routes increases with the increase of the deformation,and the dislocation density of the route A is always greater than that of the route C.