Analysis of High Temperature Ni Brazing via 3D µXCT & Differential Scanning Calorimetry

部件维修对航空发动机和工业燃气轮机的生命周期至关重要，可以延长寿命，从而减少成本和环境浪费。构成燃气轮机热段部件的镍基高温合金通常使用粉末基钎焊工艺或线基焊接工艺进行修复。铜焊是有利的，因为它能够填充结构裂缝和重建复杂的部件段，而不会与母材过度相互作用。与焊接不同的是，钎焊不需要熔化工件。 虽然通过粉末冶金修复的镍高温合金部件的最终物理冶金和机械性能已知很多，但对其在钎焊过程中发生的潜在机理了解有限。在与Liburdi涡轮机服务公司的这项合作研究中，将开展一项以实验为基础的研究项目，以表征Liburdi粉末冶金(TM)修复过程中各种焊接材料之间的物理结构和不断演变的相互作用。将利用先进的原位和OPANDO 3D X射线计算机断层扫描显微镜和差示扫描量热技术来创建显示材料结构演变的3D图像库，并用对相应相变的定量洞察来补充这些图像。研究结果将使Liburdi能够改进他们的工艺，为燃气轮机应用中使用的镍高温合金部件创造高强度修复。

Component repair is critical for the lifecycle of aero-engine and industrial gas turbines, increasing lifespan thus reducing costs and environmental waste. The Ni based superalloys that comprise the hot section components of a gas turbine are typically repaired using a powder-based brazing process or a wire-based welding process. Brazing is advantageous because of its ability to fill structural cracks and rebuild complex components segments while not interacting excessively with the base metal. Unlike welding, brazing does not involve melting of the workpiece. Although much is known of the final physical metallurgy and mechanical properties of a Ni superalloy component repaired via powder metallurgy, there is limited knowledge regarding the underlying mechanisms occurring during brazing. In this collaborative study with Liburdi Turbine Services, an experimentally-based research project will be undertaken to characterize the physical structure and evolving interactions between the various brazing materials during the Liburdi Powder Metallurgy(TM) repair process. Advanced in situ and operando 3D X-ray computed tomographic microscopy and differential scanning calorimetry techniques will be utilized to create a library of 3D images showing the structural evolution of the material, and to supplement these images with quantitative insight of the corresponding phase transformations. The research results will enable Liburdi to improve their processes for creating high-strength repairs of Ni superalloy components used in gas turbine applications.