Microstructure Evolution And Properties Of Serve Deformed Cu-Cr-Si Alloy

With the rapid development of national economy and science and technology,the industrial field puts forward higher requirements for the materials properties.Cu-Cr-Si alloy has a wide application prospect as a highly conductive material,but the balance of mechanical properties and electrical conductivity has become an important issues.In response to this problem,the multi-pass extrusion has been carried outbyequal channel angular extrusion(ECAP)technology forCu-Cr-Si alloy with route A and C,and the samples after deformation wereaging at 350? and 400? in different times(1h,2h,4h,6h,8h);the microstructure,macro orientation,micro orientation,and precipitation phase of the alloy after deformation and aging treatment were characterized by OM,SEM,XRD,EDS,EBSDtechnology,The mechanical properties and electrical conductivity of the alloy were tested.The causes of the microstructure evolution and mechanical properties of the alloy after deformation and aging were analyzed.The evolution of the texture was revealed,and the relationship between material structure and texture as well as the coupling effect between them and material properties in the process of deformation and aging treatment was explored;and optimizes the aging process of Cu-Cr-Si alloy.The results show that in the process of ECAP deformation,the grain gradually transforms into fiber structure under medium and low strains.And under high strain,some grains break and turn into short rods,and the route Ahas a stronger refinement effect than route C.After multi-pass deformation of the alloy,the tensile strength and elongation of the route Ais larger,reaching 573.5MPa and 10.46%,and the electrical conductivity is still maintained at 70.2% IACS.The fracture characteristics ind icate that the alloy gradually changes from ductile fracture to brittle fracture.During the deformation process,the main slip surface always maintains t he(111)crystal plane,while the sub-slip surface alternates between the(200)and the(220)crystal plane,and whichindicatescrystal has obvious intersection slip characteristics.At the initial stage of aging,the fine point or short rod-shaped Crx Si phase and Crsimple substance are mainly distributed along the grain boundaries(GBs).With the aging time prolonged,the precipitated phase gradually grows to about 10 10?m,showing an irregular shape,and the number of phase in the matrix is gradually increasing.The hardness and strength of the material after aging treatment decreased,while the electrical conductivity and elongation increased,and the electrical conductivity at 350? was always higher than 400?.After deformation,the alloy gradually changes from ductile fracture to brittle fracture.After aging treatment,the fracture of the alloy is ductile fracture.but itturninto brittle fracture at high pass.The best aging processis aging for 4 hours at 350 ?,at this time the strength,hardness,conductivity of alloy achieve the best balance.After aging,the micro-texture of the two kinds of route is mostly segregated on the(110)crystal plane,and after 8 passes,a stable(111)<110> texture is formed inside the crystal,The presence of(111)<110>texture increases the electrical conductivity of the material.The dislocation de nsity inside the crystal was calculated after deformation and aging treatment,and it was found that the dislocation density of both route decreased with the increase of deformation.Combined with the strength change of the material after aging,it is found that the effect of deformation strengthening is far stronger than that of aging strengthening,but the aging treatment improves the balance of material strength and conductivity.There is a necessary relationship between organization,texture and material properties.Organizational evolution seriously affects the transformation of texture,and organization and texture determine the performance of materials from macro and micro perspectives.