微/纳双尺度颗粒增强铜基复合材料原位反应合成规律及协同强化机制

In-situ synthesized particulate reinforced copper matrix composites can effectively exert load transfer and distribution of enhanced phases due to the good interface between the matrix and the reinforcing phases. However, the reaction process of reinforced particles in copper melt is difficult to intervene manually, and it is easy to produce incomplete reaction and residual solute elements, thereby impairing the conductivity of the materials. At the same time, the second phase particles reacting spontaneously are mostly on the order of micrometers, and the second phase strengthening effect is very limited. The project will optimize with Cu-Zr-B ternary composites system. By in-situ reaction and aging treatment process, a two-scale particle reinforced copper matrix composite containing both micron ZrB2 and nano-rich Zr phase will be prepared. By means of phase equilibrium thermodynamic calculation, aging kinetic calculation and microstructure characterization, the control factors and influence laws of authigenic particle reaction synthesis will be clarified. The synergistic strengthening mechanism and high temperature softening mechanism of dual-scale particles in high temperature mechanics and friction and wear of dual-scale particles will be revealed. The mechanism of the influence of arc erosion resistance of composite materials provides a theoretical basis for the design and development of new micro/nano double-scale particles reinforced copper matrix composites. The mechanism of influence on the corrosion resistance of composite materials. Finally, it will provide a theoretical basis for the design and development of novel micro/nano dual-scale particles reinforced copper matrix composites.

原位自生颗粒强化铜基复合材料由于基体与增强相之间界面良好，可有效发挥增强相载荷传递/分配作用。然而，熔体中增强颗粒原位反应过程人工干预难度大，易反应不完全而使溶质元素残余，从而损害材料导电性能；同时，反应自生的第二相粒子多处于微米量级，第二相强化效果十分有限。本项目以Cu-Zr-B三元复合材料体系进行优化设计，结合原位反应和时效处理工艺，制备同时含有微米ZrB2和纳米富Zr相的双尺度颗粒强化铜基复合材料。借助相平衡热力学计算、时效析出动力学计算和组织表征，明确自生颗粒反应合成控制因素及影响规律；阐明双尺度颗粒高温力学和摩擦磨损过程中的协同强化机制和材料高温软化机理；揭示双尺度颗粒对复合材料耐电弧侵蚀性能影响机理。从而为新型微/纳双尺度颗粒增强铜基复合材料的设计与开发提供理论依据。

颗粒增强铜基复合材料具有优异的导电导热性、高强度和耐摩擦磨损特性，因此在高强高导材料需求领域具有广阔的应用前景。在本项目资助下，通过原位反应熔铸法和后续热处理工艺成功制备了一种新型双尺度颗粒增强Cu-Zr-ZrB2复合材料，并通过不同温度和时间下的热处理研究了原位ZrB2颗粒对固溶Zr析出的影响规律，结果表明时效时间120 min、时效温度400°C的双尺度颗粒强化铜基复合材料具有良好的强度、导电性平衡。通过XRD、扫描电镜和能谱仪分析发现材料中微米级颗粒为ZrB2，由铜熔体中的Zr和B元素原位反应形成；透射电镜图像和电子衍射图表明纳米级析出相为Cu5Zr，由铜基体中的Zr元素经固溶和时效处理之后析出形成。在微纳颗粒协同强化下，铜基复合材料抗拉强度达到621 Mpa，维氏硬度达到218 HV，并且其电导率仍能保持在83.0 %IACS。本项目的研究对发展高强高导耐磨铜基材料具有积极的科学意义。