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

部件维修对于航空发动机和工业燃气轮机的生命周期至关重要，可以延长使用寿命，从而降低成本和环境浪费。包括燃气涡轮机的热段部件的Ni基超合金通常使用基于粉末的钎焊工艺或基于焊丝的焊接工艺来修复。钎焊是有利的，因为它能够填充结构裂缝和重建复杂的部件段，同时不与基体金属过度相互作用。与焊接不同，钎焊不涉及工件的熔化。 虽然通过粉末冶金修复的镍超合金部件的最终物理冶金和机械性能已知很多，但关于钎焊过程中发生的潜在机制的知识有限。在与Liburdi涡轮机服务公司的这项合作研究中，将进行一项基于实验的研究项目，以表征Liburdi粉末冶金（TM）修复过程中各种钎焊材料之间的物理结构和不断变化的相互作用。先进的原位和operando三维X射线计算机断层扫描显微镜和差示扫描量热技术将被用来创建一个三维图像库，显示材料的结构演变，并补充这些图像与相应的相变的定量洞察。研究结果将使Liburdi能够改进其工艺，以创建用于燃气涡轮机应用的镍高温合金部件的高强度修复。

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.