Study On The Effect Of Sn Element And Solidification Process On The Microstructure And Properties Of Cu-5Fe Alloy

Cu-Fe alloys are commonly used in magnetic conductive materials,electrical discharge processing materials and electromagnetic shielding materials due to their low cost,high strength and hardness,excellent elasticity and electrical conductivity,and unique soft magnetic properties.In this paper,the Cu-5Fe-x Sn alloy cast rod was prepared by vacuum casting and vacuum horizontal continuous casting,and the mechanism of the role of Sn elements in the solidification behaviour of Cu-5Fe alloy was explored;the Fe phase morphology,distribution and precipitation behaviour of Cu-5Fe-x Sn alloy and the evolution of its properties were systematically analysed;the effect of vacuum horizontal The effect of continuous casting process parameters on the surface quality,organization and properties of the Cu-5Fe alloy cast rod;the optimization of the deformation heat treatment process to further improve the overall performance of the alloy;and the clarification of the intrinsic link between the "process-composition-organization-properties" of the Cu-5Fe-x Sn alloy,the main experimental results are as follows:(1)The slight addition of the Sn element decreases the extent of the solid solution of Fe in Cu,which promotes the nucleation and precipitation of the γ-Fe phase and refines the primary Fe phase,making it uniformly distributed in the Cu matrix in a granular form.the addition of the Sn element reduces the activation energy of the precipitation of the Fe phase,which accelerates the precipitation of the Fe phase and suppresses its coarsening.(2)After the multi-stage metamorphic heat treatment,the spherical Fe phase is fibrillated and the Fe fibers maintain a semi-co-grained relationship with the Cu matrix.the addition of Sn elements optimizes the distribution of the Fe fibers,making them more continuous and dense and improving the thermal stability of the Fe fibers.The uniform solid solution of Sn elements in the Cu matrix enhances the work-hardening effect of the Cu-5Fe alloy,improves the Cu/Fe synergistic deformation ability,inhibits recrystallisation and grain coarsening of the Cu matrix,and significantly improves the mechanical properties of the Cu-5Fe alloy.(3)By regulating the parameters of the vacuum horizontal continuous casting process,Cu-5Fe-0.15 Sn alloy rods with good surface quality and homogeneous composition were achieved at a melt temperature of 1270 ℃,a counter-thrust stroke of 0.3 mm and a traction speed of 0.05-0.2 m/min.As the traction speed increased,the size of the primary Fe phase and the number of Fe dendrites were reduced,the Fe phase was more uniformly distributed,and both dendritic and spherical Fe phases were transformed into Fe fibres after the deformation heat treatment,and the Fe fibre spacing decreased with increasing traction speed.(4)At a traction speed of 0.15 m/min,Cu-5Fe-0.15 Sn alloy had better overall performance,and Cu-5Fe-0.15 Sn alloy wire of Φ0.6 mm was prepared by the homogenization(950 ℃ × 2 h)-drawing(η=5.6)-annealing(450 ℃ × 4 h)-drawing(η=7)-aging(400 ℃ × 1 h)process.The strength,electrical conductivity and softening temperature of the wire reached 785 MPa,66.8% IACS and 450 °C.With the same deformation heat treatment process,the tensile strength,electrical conductivity and softening temperature of the alloy wire produced by vacuum horizontal continuous casting are increased by 50 MPa,2% IACS and 50 ℃ respectively compared to vacuum casting.