| Cu-Ni-Si alloy is a typical age-reinforced alloy,which has the advantages of high strength,high conductivity,good welding performance,relatively low price and so on.It has been widely studied in electronics,automobiles,Aerospace and other fields have good application prospects.Especially when applied to lead frame materials,Cu-Ni-Si series alloys show significant comprehensive advantages and have become an important development direction of copper-based lead frame materials.In this paper,by adding trace Mg and rare earth element Ce,the as-cast plate of Cu-2.25Ni-0.5Si-0.05Mg-0.05 Ce alloy was obtained,followed by homogenization treatment at 900?×2h.The homogenized alloy is then subjected to different cold rolling deformations(38%,61%,81%,95%).Choose an alloy with a cold rolling reduction rate of 95% under different solution treatment conditions(800?×1h,850?×1h,900?×1h,850?×1min)for different aging temperatures(400?,450?,500 ?,550 ?),different aging time(0.5h,1h,2h,4h,6h,8h)treatment,to study the microcosm of Cu-Ni-Si-Mg-Ce alloy during large deformation cold rolling and aging treatment Changes in organization,mechanical properties and electrical conductivity.The main research results obtained in this paper are as follows:(1)With the increase of cold rolling deformation(from 0% to 95%),the microstructure of Cu-Ni-Si-Mg-Ce alloy changes significantly.When the cold rolling deformation is 38%,obvious shear bands appear inside the grains,and there is no obvious regularity of the shear direction.When the cold rolling deformation is 61%,the shear bands increase significantly and interlace,forming a shear band In the network,when the cold rolling deformation increases to 81%,parallel deformation bands appear in the grains.When the cold rolling deformation is 95%,the grain boundaries are broken and blurred,and the grains show parallel distribution of fibers under the effect of cold rolling Like organization.(2)With the increase of cold rolling deformation(from 0% to 95%),a large number of dislocations are generated inside the Cu-Ni-Si-Mg-Ce alloy and a shear band composed of high-density dislocations is formed,resulting in the alloy The microhardness and tensile strength gradually increase,and the elongation gradually decreases.(3)With the increase of cold rolling deformation(from 0% to 95%),a large number of dislocations and other defects in the Cu-Ni-Si-Mg-Ce alloy cause the lattice distortion of the matrix,increasing the probability of electron scattering,Hindering the movement of free electrons,resulting in a slight decrease in the electrical conductivity of the alloy as the amount of cold rolling deformation increases.(4)Select the Cu-Ni-Si-Mg-Ce alloy with a cold rolling deformation of 95%,and then undergo solution treatment at 800?×1h,850?×1h,900?×1h,850?×1min,and then After different aging temperatures(400 ?,450 ?,500 ?,550 ?),and the same aging time(all 4h),it is found that the alloys under different solid solution conditions show similar laws after aging,with With the increase of aging temperature,the microhardness and tensile strength first increase and then decrease,and reach the peak value at 450?.(5)Under four different solution treatment conditions,Cu-Ni-Si-Mg-Ce alloy shows that as the aging temperature increases,the conductivity increases first and then decreases.Under the same heat treatment conditions as in Article 4,the alloys show that as the aging temperature increases,the conductivity increases first and then decreases.(6)The Cu-Ni-Si-Mg-Ce alloy with 95% cold rolling deformation was subjected to solution treatment at 800°C × 1h,850°C × 1h,900°C × 1h,and 850°C × 1min,followed by The temperature is 450?,and the aging treatment at different times(0.5h,1h,2h,4h,6h,8h).It is found that the microhardness and tensile strength of the alloy under different solid solution conditions with the extension of the aging time.It showed a trend of increasing first and then decreasing,and most of them reached the peak value at 4h.(7)Under the four solution treatment conditions,the conductivity of Cu-Ni-SiMg-Ce alloy at different aging times is shown as the electrical conductivity gradually increases with time,and the initial growth rate of aging is more Big.(8)After the cold rolling deformation is 95%,the Cu-Ni-Si-Mg-Ce alloy has the best comprehensive performance after 850?×1h solution treatment and 450?×4h aging treatment.At this time,the microhardness is 211 HV,Tensile strength is 440 MPa,conductivity is 46.2% IACS. |
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