高硬导电Cu-Ni-Si系铜合金强化相成分设计

Phase-composition design of high-hardness and high-electric-conductivity Cu-Ni-Si Alloy

Cu-Ni-Si系铜合金有良好的导电、导热和机械性能,被广泛用于电子元器件等领域.设计Cu-Ni-Si系铜合金成分时,析出相成分的确定是关键.本文利用团簇加连接原子模型方法按"析出相"设计Cu-Ni-Si系铜合金的成分.依据团簇选取准则,选定d-Ni2Si,γ-Ni5Si2和β-Ni3Si相团簇式分别为[Ni-Ni8Si5]Ni,[Si-Ni10]Si3和[Si-Ni12]Si3;在基体Cu含量原子分数为93.75%,95%,95.83%,96.7%和97.5%的每一成分点处,分别按析出相δ-Ni2Si,γ-Ni5Si2和β-Ni3Si设计了系列Cu-Ni-Si合金的成分.合金原料在充满氩气的真空电弧炉中熔炼成合金锭,经950°C/1 h固溶水淬和450°C/4 h时效水淬处理.当合金的导电性成为成分设计的主因时,基体Cu含量分别在90%-95.63%和95.63%-97.5%成分区间时,析出相分别按d-Ni2Si和γ-Ni5Si2设计;基体Cu含量大于97.5%,按d-Ni2Si,γ-Ni5Si2或β-Ni3Si中任一相设计均可,导电性基本没有差别.如果合金的强度是成分设计的主因,基体Cu含量分别在90%-93.93%,93.93%-94.34%,94.34%-95.63%和95.63%-96.12%成分区间时,析出相对应于上述成分区间分别按d-Ni2Si,γ-Ni5Si2,β-Ni3Si和γ-Ni5Si2设计;基体Cu含量一旦大于96.12%,析出相按d-Ni2Si,γ-Ni5Si2或β-Ni3Si中任一相设计均可.

Cu-Ni-Si alloy has good electrical conductivity,thermal conductivity,high strength,and high hardness,and is widely used in electronic components and other fields.When the compositions of the Cu-Ni-Si alloy are designed,the determination of the phase component is critical.In this work,the composition of Cu-Ni-Si alloy is designed according to the "precipitation phase" by cluster-plus-glum-atom model.Following the cluster selection criteria,the δ-Ni2Si,γ-Ni5Si2 and β-Ni3Si phase clusters are determined,respectively,and the corresponding cluster formulas are [Ni-Ni8Si5]Ni,[Si-Ni10]Si3,and [Si-Ni12]Si3.the compositions of a series of Cu-Ni-Si alloys are designed according to the different precipitated phases of δ-Ni2Si,γ-Ni5Si2,and β-Ni3Si each with Cu atom content being 93.75%,95%,95.8%,96.7% and 97.5%,respectively.The alloy raw material is melted into alloy ingot in an argon-filled vacuum arc furnace.The ingots undergoes soliδ-solution at 950 ℃ for 1 hour and water quenching then aging treatment at 450 ℃ for 4 hour and water quenching.The conductivity and Vickers hardness of the alloy are tested by conductivity meter and hardness meter,respectively.The microstructure of the alloy is characterized by x-ray diffraction(XRD),scanning electron microscopy(SEM),and transmission electron microscopy(TEM).In general,the electrical conductivity of Cu-Ni-Si is the main consideration in the design of alloy composition,the content values of matrix Cu atoms are in the ranges of 90%-95.63% and 95.63%-97.5% respectively,the precipitated phases are designed according to δ-Ni2Si and γ-Ni5Si2 respectively;the content of matrix Cu atoms is over 97.5%,it can be designed according to any phase of δ-Ni2Si,γ-Ni5Si2 and β-Ni3Si,with no difference in electrical conductivity among them.If the strength of the alloy is the main factor in the composition design,the content values of Cu atoms in the matrix are in the ranges of 90%- 93.93%,93.93%- 94.34%,94.34%- 95.63%,and 95.63%-96.12% respectively,according to the composition intervals the precipitated phases are designed as δ-Ni2Si,γ-Ni5Si2,β-Ni3Si,and γ-Ni5Si2,respectively.Once the content of Cu in the matrix is greater than 96.12%,the precipitated phase can be designed according to any of the phases of δ-Ni2Si,γ-Ni5Si2 and β-Ni3Si.