Study Microstructure And Properties Of Cu-Cr-Fe-Ni Alloy

Cu-Cr alloy is a precipitation-strengthened alloy with good comprehensive properties,which is widely used in rail transportation,electrical and electronic industries,and the addition of trace alloy elements can further optimize the overall performance of Cu-Cr alloy.In this paper,Fe and Ni are selected as trace addition elements,with pure Cu(99.95 wt.%),Cu-8.0wt.% Cr master alloy,pure Fe(99.9 wt.%),Pure Ni(99.99 wt.%)As raw materials.Cu-Cr-Fe-Ni series quaternary alloys were prepared by atmospheric smelting,using X-ray diffraction,metallography(OM),scanning electron microscopy(SEM),energy spectrometer(EDS),transmission electron microscopy(TEM),etc.Test method to study the effects of different Ni content,hot working,solution treatment,cold deformation,and aging treatment on the hardness,conductivity and microstructure evolution of the alloy.Research indicates:The Cu-0.59Cr-0.078Fe-0.081 Ni alloy undergoes non-vacuum smelting to form a dendritic structure.The elements of Fe and Ni are evenly distributed in the matrix.Part of the Cr element is dissolved in the matrix and part of it is enriched in the form of the second phase In the gap between dendrites.After hot rolling of the sample alloy,the grains are twisted and deformed,and the changes in hardness and electrical conductivity are not obvious.After solid solution at 950 ? × 1 h,the Cr-rich phase initially enriched between the dendrites and the grain boundaries dissolves.Resulting in a reduction in the hardness and electrical conductivity of the alloy,respectively,compared with the hot-rolled samples reduced by 21.5 HV0.2,3.5% IACS.The sample alloy was aged at 450 ? after solid solution,and the hardness of the alloy reached a peak value of 121.9 HV0.2 at 2 hours of heat preservation.At this time,the electrical conductivity was 80.5% IACS.The alloy undergoes cold deformation before aging.When the amount of cold deformation reaches 40%,the hardness value of the alloy is increased by 62.7 HV0.2 compared with that without deformation.When the amount of cold deformation increases to 90%,the hardness of the alloy reaches the maximum value of 144.7 HV0.2.After the sample alloy undergoes aging treatment after cold deformation,its hardness is further improved compared with aging treatment after solid solution,and with the extension of aging time,its hardness shows a trend of first increasing and then decreasing.When the amount of cold deformation reaches 60% and 450 ? After aging for 30 min,the hardness of the alloy reaches a maximum value of 155.5 HV0.2,at which time the conductivity is 71.4% IACS.The Cu-Cr-Fe-Ni alloy is added with different amounts of Ni element,and the Ni element content will change the appearance of the primary Cr phase.When the Ni content is 0.048 wt.%,The primary Cr phase is elongated;when the Ni content is 0.086 wt.%,It is rod-shaped;when the Ni content is 0.086 wt.%,The primary Cr phase is plate-shaped.As the Ni content increases,the primary Cr phase becomes coarser.For Cu-Cr-Fe-xNi alloys with different Ni contents,an increase in the Ni element content can effectively increase the hardness of the alloy.The Cu-Cr-Fe-xNi alloy with a Ni content of 0.14% is kept under solution aging for 20 minutes,The hardness and conductivity of the sample alloy can reach 159.5 HV0.2 and 63.8% IACS,respectively.