Study Microstructure And Properties Of Cu-3Ti-0.2Fe-xSn Alloy

Cu-Ti alloy has excellent strength,stress relaxation resistance,high temperature softening resistance,fatigue resistance and corrosion resistance,etc.When Ti is contained in 1-5 wt.%,the mechanical and physical properties of the alloy are comparable to those of Cu-Be alloy,which is the "king of colored elastic materials".However,the alloy has a low conductivity problem.In this project,the conductivity of Cu-Ti alloy was improved by adding Fe and Sn trace alloying elements and subjecting the resulting alloy to solid solution,cold deformation aging and combined aging treatment.Cu-3Ti-0.2Fe-x Sn quaternary alloy was prepared by vacuum melting method,and the changes in the organization and properties of the alloy with different Sn contents added were studied to determine the optimized Sn content to be added to the alloy;the Cu-3Ti-0.2Fe-Sn alloy was subjected to solid solution,aging and cold deformation treatment to determine the optimized processing process parameters.The following results were obtained from the study.(1)The addition of Sn content of 0,0.2 wt.%,0.5 wt.%,1.0 wt.% Cu-3Ti-0.2Fex Sn four groups of test alloys were subjected to 850 ℃×240 min solid solution +60% cold deformation 450 ℃ initial aging + 90% cold deformation and then aging treatment,it was found that the addition of Sn elements in the alloy can increase the hardness of the treated alloy,Cu-3Ti-0.2Fe-0Sn hardness peak of 290.13 HV,Cu-3Ti-0.2Fe-0.2Sn hardness peak of 334.2 HV,Cu-3Ti-0.2Fe-0.5Sn in hardness peak of339.7 HV,Cu-3Ti-0.2Fe-1Sn hardness peak of 333.3 HV.(2)The hardness and electrical conductivity of all four test alloys increased after90% final cold rolling and then aging,compared with the initial cold rolling and initial aging alloys,and the hardness and electrical conductivity of the Cu-3Ti-0.2FeSn alloy with 1% Sn added reached 300 HV and 22 %IACS after final cold rolling and then aging for 120 min;the better addition of Sn in the alloy was 1.0 wt.%.(3)In the as-cast Cu-3Ti-0.2Fe-Sn alloy prepared by vacuum melting,Ti and Sn elements are partially dissolved in the matrix,and some of them form rich(Ti、Sn)phases enriched in the dendrites,and Fe elements are uniformly distributed in the matrix;after the alloy is solid solution treated at 850°C×240 min,the rich(Ti、Sn)phases enriched in the dendrites are dissolved,and at this time the residual phase in the matrix is Fe Ti-rich.The residual phase is the Fe Ti-rich phase.Due to the solid solution of a large number of Ti and Sn elements into the copper matrix,the electrical conductivity and hardness of the alloy are reduced accordingly;compared with the ascast state,the electrical conductivity of the solid solution alloy decreases by6.27 %IACS and the hardness decreases by 75.8 HV.(4)Cu-3Ti-0.2Fe-Sn alloy after different solid solution temperature treatment for240 min,determine the Cu-3Ti-0.2Fe-Sn solid solution temperature of 850°C ×240min,before the aging selected deformation amount of 0,40%,60%,80% of its cold deformation,the alloy 60% deformation aging compared to other deformation variables have excellent resistance to After examining the effect of aging temperature(400°C,450°C,500°C)on the alloy properties,it was found that the hardness and electrical conductivity of the alloy reached 310.2 HV and 18.59 %IACS when the cold deformation amount was 60% and the aging temperature was 450°C for 480 min;the optimized solution and deformation heat treatment process of the alloy was:850°C×240 min solution + 60% cold deformation + 450°C aging.