【作者】 苏娟华；

【导师】 李贺军； 董企铭； 刘平；

【作者基本信息】 西北工业大学 ， 材料学， 2006， 博士

【摘要】 随着电子信息产业的高速发展，对集成电路主要组成部分之一的引线框架铜合金材料的性能要求越来越高。理想的引线框架材料的主要性能为：抗拉强度在600MPa以上，显微硬度大于180HV，导电率大于80％IACS。而目前所开发出的铜合金材料很难满足其性能要求，所以研制和开发可满足大规模集成电路需要的同时具有高强度和高导电性的铜合金材料是研究热点之一。 根据高强高导铜合金的强化机理和对性能的要求，本文在分析合金元素在铜合金中作用的基础上，确定了高强高导引线框架铜合金材料的最佳合金系为Cu-Cr-Zr系。 利用透射电镜研究了Cu-Cr-Zr-Mg和Cu-Cr-Zr合金的组织转变规律，发现Cu-Cr-Zr-Mg合金在470℃时效形成了具有Fm₃m点群的超点阵CrCu₂（ZrMg）；同时存在体心的Cr相和面心的Cu₄Zr相。高温550℃时效析出相完全转变为Cr和Cu₄Zr。Cu-Cr-Zr合金在时效初期形成Cu₅Zr相，时效峰值状态析出相为Cu₅Zr相和体心立方的Cr，且析出相与基体保持着共格关系。以共格强化机制计算的强化值407MPa与实验结果430MPa相近。 在分析Cu-Cr-Zr-Mg合金时效过程中导电率变化规律的基础上，利用合金时效过程中析出相的体积分数与导电率的线性关系，推导出实验温度下合金时效的Avrami相变动力学方程与导电率方程，并通过计算绘制了该固溶合金等温转变动力学（TTT）曲线。 系统研究了Cu-Cr-Zr合金变形时效后，析出和再结晶的交互作用及其对组织和性能的影响。在低于550℃时效，沿位错分布着很多细小的析出相，使硬度和导电率在时效初期快速提高。同时析出物对位错的钉扎作用，延缓了再结晶过程。在一定的变形程度和较高温度时效后，由位错缠结成的胞状结构在时效过程中胞壁平直化，并形成亚晶，小角度晶界上的刃位错通过攀移而离开亚晶界，使两个亚晶变成一个大亚晶，出现了再结晶形核和长大的现象。 采用L-M算法分别建立了引线框架Cu-Cr-Zr-Mg合金和Cu-Cr-Sn-Zn合金形变热处理工艺和时效工艺的人工神经网络模型，预测和研究了时效工艺参数性能的耦合作用，并且利用三维立体图将其直观地表达出来，得出了时效温度、时效时间和变形量工艺参数对硬度和导电率的影响规律，为工艺参数优化更多还原

【Abstract】 With the development of large-scale integrated circuit, higher mechanical and electrical properties of copper alloys for lead frame are required. The ideal requirement for lead frame material properties is that tensile strength, hardness and electrical conductivity are more than 600MPa, 180HV and 80%IACS respectively. The copper alloy materials developed at the present time are difficulty in meeting the needs of high performance. So the study on the copper alloy material for lead frame used in the large-scale integrated circuit attracts much more attention.According to the strength mechanism and comprehensive property demands, the effect of alloying elements on copper alloy properties is analyzed. The optimal copper alloy is Cu-Cr-Zr for high strength and high conductivity lead frame materials used in integrated circuit.By transmission electronic microscope, aging precipitation phase transformation of Cu-Cr-Zr-Mg and Cu-Cr-Zr alloys was dealt with. After solid solution treated at 920℃ and aged at 470℃ for Cu-Cr-Zr-Mg alloy, the fine precipitation of an ordered compound CrCu₂（Zr,Mg） is found in copper matrix as well as fine Cr and Cu₄Zr. Aged at higher temperature the precipitate phases are completely transformed into Cr and Cu₄Zr. For Cu-Cr-Zr alloy at the early stage of aging, precipitate phase Cu₅Zr is formed. Aged at the same temperature for 6h, the precipitate phases are Cu₅Zr and Cr, which is associated with the peak hardness condition in the alloy. The precipitates are coherent with copper matrix. The strength 407MPa derived from coherent strengthening is almost identical with the experimental value 430MPa.Upon aging after solid solution for the Cu-Cr-Zr-Mg alloy, there could be linearity between electrical conductivity and volume fraction of precipitates. Based on the linear relationship, Avrami phase transformation kinetics equation and electrical conductivity equation at different aging temperatures are described for the Cu-Cr-Zr-Mg. The time-temperature-transformation （TTT） curves are also established.The mutual action between the aging precipitation and recrystallization and their effect on the microstructure and properties are dealt with systematically. Aged at the temperature lower than 550℃, it is found that the dislocations provide nucleation site for precipitation and the dispersed precipitates distribute along the dislocation, resulting in the precipitation hardening effect. At the same time the dislocations are pinned by the dispersed precipitates, the following recrystallization process is hindered. Rolled at definite extent of deformation and aged at higher temperature, the cell substructures formed by dislocation walls first appear strip structure. Then the bulging of the boundaries of some cell substructures and annihilation of the dislocations inside the cells indicate the onset and growth of recrystallization. The development of recrystallization offsets the hardening of the Cu-Cr-Zr alloys.For the first time, artificial neural network models of thermomechanical treatment processes and aging processes for Cu-Cr-Zr-Mg alloy and Cu-Cr-Sn-Zn alloy are established by更多还原