Cu-Ni-Al合金中沉淀相的析出调控及其对载流摩擦学特性的影响

Because of the higher solutionability in Cu, lower demage to Cu matrix of being solved than Si, and the similar ability to form intermetallics with Ni, Cu-Ni-Al alloys are expected to have higher combination of strength and electrical conductivity than Cu-Ni-Si alloys, which are well recognized as one of the best Cu alloy system with high strength and electrical conductivity. In this proposal, the crystal structure and chemical composition of precipitates will be analyzed, the thermodynamic model of precipitation process will be established, and the phase transformation behavior as well as its dynamics mechanism will be also investigated systemically. On the other hand, the interaction mechanism of arc erosion and mechanical friction in the case of friction and wear with electrical current will be investigated by studying the character parameters and surface morphologies of sample with different treating conditions under three different conditions, viz. static arc breakdown, friction and wear with and without electrical current. As a result, the critical condition of precipitates form from single-phase solution in the Cu-rich corner of Cu-Ni-Al ternary phase diagram as well as its dynamic mechanism, friction and wear mechanism with electrical condition as well as its relationships with microstructral characters of Cu-Ni-Al alloys, will be clarified finally. On this basis, the control on the precipitation process and precipitation feature as well as its influence on strength, electrical conductivity and wear performance with current can be realized. The results can be presented as an important theoretic and experimental guidance for the preparation and application of Cu-Ni-Al alloys with high strength, high electrical conductivity and good wear performance.

与Si元素相比，Al元素在铜中的固溶度更高、固溶对铜基体导电率的损伤更小且同样能与Ni元素形成金属间化合物，Cu-Ni-Al合金有望比目前广泛研究的高强高导Cu-Ni-Si合金获得更佳的强度与导电率组合。本项目拟通过对沉淀相晶体结构表征和化学成分分析、析出过程热动力学模型的建立以及沉淀相析出行为和动力学规律研究等探讨Cu-Ni-Al三元相图富铜端单相固溶区内析出沉淀相的临界条件与动力学机制，并在静态电弧烧蚀、机械摩擦和载流摩擦三种不同工况对Cu-Ni-Al合金的电击穿参数和摩擦学参数进行对比研究，结合表面形貌分析探讨载流摩擦过程中电弧烧蚀与机械摩擦的耦合规律，从而解决“调控沉淀相特征的相变行为与理论”和“载流摩擦机制及其与沉淀相特征的依存关系”这两方面的关键科学问题，为开发一种新型的高强度、高导电性和良好耐磨性的Cu-Ni-Al合金及其作为接触线材料的工程应用提供理论和实验依据。

兼具高强度和高导电性的引线框架材料，是应对集成电路向更高集成度、更多器件承载量发展的关键。与目前最具高强度和高导电性潜质的Cu-Ni-Si合金相比，Al元素比Si元素在铜中的固溶度更高、固溶对铜基体导电率的损伤更小，且同样能与Ni元素形成金属间化合物，因而从理论上讲更具高强高导潜质。然而，由于现有Cu-Ni-Al三元相图富Cu端被认为是单相固溶区，Cu-Ni-Al合金并未被作为高强度和高导电性合金的候选者。本项目首先采用熔铸法制备了成分位于相图单相固溶区的三种不同Ni、Al含量的Cu-Ni-Al合金，利用XRD、EDS和HRTEM等手段对其进行了详细表征，确定了铸态合金中析出相的结构，证实了Cu-Ni-Al合金三元相图富Cu端单向固溶区能够析出Ni-Al化合物；其次，基于Gibbs自由能方程和考虑动力学因素的Miedema模型对Cu-Ni-Al合金中化合物相的竞争形成过程进行计算，发现在凝固过程NiAl相由于具有最低的吉布斯自由能变而优先形成，但在固态相变过程Ni3Al相因具有相对较低的生成焓以及最小的Al元素含量而优先析出；随后，通过正交实验对固溶和时效工艺参数进行了调节，发现工艺参数调整虽从一定程度上能够改变合金的硬度和导电率，但改变的效果并不明显，故进一步研究了添加微量Ti元素以及热处理和热机械处理相结合的方式，对合金中沉淀相的析出动力进行了调控，发现Ti元素的添加能够增加时效过程中析出相的生成，使得合金导电性能和硬度都有一定程度的提升；最后，对不同处理状态下的Cu-Ni-Al(Ti)合金在不同条件下进行摩擦磨损实验，解析了机械摩擦和电流引入对合金摩擦学性能的影响，发现随着电流的增加，黏着磨损加剧，且导电率的提高能够从一定程度上减小摩擦系数和磨损量。本项目的研究结果证实了Cu-Ni-Al合金的高强度和高导电性潜质，也可为其制备和性能优化以及工程应用提供一定的理论和实验基础。

内容获取失败，请点击重试