高通量开发锆铜/镍基高温合金瞬时液相扩散焊中间层及接头形成机理

Transient liquid phase diffusion bonding (TLP) is the core technology of fabricating the inner wall of copper alloy and the outer wall of superalloy in the combustor of high-thrust rocket engines, selection of the proper interlayer material is the key to achieve high quality TLP bonded joint. To solve the problem of low efficiency and over-reliance on experience in traditional design of interlayer materials, this project proposes a new method based on high-throughput preparation and characterization experiments to develop TLP diffusion bonding interlayer. Firstly, the amorphous foil interlayer with a certain composition range is prepared at one time, and then the interlayers with multiple composition ratios are used for TLP bonding, and a variety of material analysis methods are used to comprehensively characterize the bonding quality. Interlayer melting and joint solidification behavior, interlayer element diffusion and interface reaction mechanism, influence of composition ratio of interlayer on microstructure and performance of the joint will be emphatically studied, so as to establish the corresponding relationship between the interlayer composition, joint microstructure and joint properties, then reveal the formation mechanism of TLP bonded joint of zirconium copper alloy and Ni-based superalloy, finally determine the optimal composition ratio of the interlayer material. The outcomes can lay a theoretical foundation for the manufacture of high-thrust rocket engine combustor, and can also be extended to develop TLP bonding interlayer for other similar and dissimilar materials, which has important technical significance and broad application prospects.

瞬时液相扩散焊（TLP）是大推力火箭发动机燃烧室铜合金内壁与高温合金外壁焊接制造的核心技术，而合理选择中间层材料是实现高质量TLP焊接的关键。针对传统方法设计中间层材料效率低且过度依赖经验的问题，本项目提出了一种基于高通量制备与表征实验开发TLP扩散焊中间层的方法。首先一次性制备具有一定成分范围的非晶箔带中间层，然后同时采用多个成分配比的中间层进行TLP焊接，并采用多种材料分析手段对焊接质量进行综合表征。重点研究中间层熔化与接头凝固行为、中间层元素扩散与界面反应机理、中间层成分配比对接头组织和性能的影响规律，最终建立中间层成分-焊缝组织-接头性能之间的对应关系，揭示锆铜合金与高温合金TLP焊接接头形成机理，并确定优化的中间层合金配方。研究成果可为大推力火箭发动机燃烧室制造奠定理论基础，还可推广于其他同种和异种材料TLP焊接中间层的开发，具有重要的技术意义和广阔的应用前景。

本项目以锆铜合金与高温合金为对象，首先进行了铜合金与镍基高温合金的直接固相扩散焊接试验，分析了固相焊接接头的显微组织和力学性能，获得了形成优良性能接头的焊接工艺参数和热处理工艺参数，并对接头的元素扩散行为与界面反应进行了分析，阐明了两种材料扩散焊接的接头形成机理。采用BNi-2中间层对铜合金和镍基高温合金进行了瞬时液相扩散焊，分析了瞬时液相扩散焊接头的显微组织和力学性能，获得了形成优良接头的焊接工艺参数，并对中间层熔化与接头凝固机理、中间层元素扩散行为与界面反应进行了分析，阐明了瞬时液相扩散焊接的接头形成机理。采用焊接难度更大的高镁含量铝合金与不锈钢作为研究对象，进一步深入研究了中间层成分对接头组织和性能的影响，获得了能够实现两种材料高性能连接的中间层合金配方，并对中间层熔化与接头凝固机理、中间层元素扩散行为与界面反应进行了分析，阐明了瞬时液相扩散焊接的接头形成机理。本项目的研究成果，对于我国未来大推力氢氧火箭发动机的研制以及载人登月和深空探测等重大航天工程的顺利实施具有重要的意义。