Welding of Single and Polycrystal Nickel Superalloys to Aluminides Based Aero-engine and Power Generation Turbine Materials by New and Emerging Joining Technologies

航空发动机涡轮用常规高温合金已达到其使用温度上限，并正在开发高温性能更高的TiAl和Ni3Al基合金。它们的使用需要焊接，以制造和修复航空涡轮机部件。这些材料还需要与传统的镍高温合金连接。镍高温合金和金属间化合物合金都极难焊接，但由于它们在化学和微观结构上的显著差异，将它们连接在一起变得更加困难。因此，拟议研究的长期目标是获得关于使用新兴焊接工艺连接当前和新一代铝化物基航空涡轮材料的科学和技术基础知识，以开发可靠的连接程序。在短期内，该研究将研究多晶IN738和单晶CSMX 486Ni高温合金与单晶Ni3Al基合金IC6焊接过程中的焊接裂纹问题，并开发无裂纹焊接的方法。这将通过使用各种填充合金的焊接实验以及在激光焊接、激光-电弧复合焊接和线性摩擦焊中使用不同工艺参数的焊前和焊后加热来实现。和过去一样，焊接实验将在标准航空公司进行。温尼伯公司和蒙特利尔的NRC航空航天制造技术中心。通过申请人实验室提供的最先进的微结构表征设备，将对焊缝的焊接裂纹和显微组织进行评估，以确定工艺参数和填充合金成分对焊缝质量的影响。然后通过数值模拟对工艺参数和填充合金成分进行优化，所建立的模型将通过进一步的实验进行验证。计划培养2名理科硕士。和2名博士生通过拟议的研究。这项研究将有助于开发基于镍和钛铝化物的新型航空涡轮材料的焊接工艺，并有助于提高加拿大航空航天公司在世界市场上的竞争地位。

Conventional high-temperature superalloys used in aero-engine turbines have reached their upper temperature application limit, and TiAl and Ni3Al based alloys with a higher high temperature capability are being developed. Their use would require them to be welded to fabricate and repair aero-turbine components. These materials would also need to be joined to conventional Ni superalloys. Both, Ni superalloys and Intermetallic alloys are extremely difficult to weld, but joining them together becomes even more challenging due to a significant disparity in their chemistry and microstructure. Therefore, the LONG-TERM objective of the proposed research is to obtain a basic knowledge of the science and technology of joining of current and new generation aluminide based aero-turbine materials using emerging welding processes to develop reliable joining procedures. In the SHORT-TERM the research will investigate the weld cracking issues during welding of polycrystalline IN 738 and single crystal CSMX 486 Ni superalloys to single crystal NI3AL based alloy IC 6, and develop methods to produce crack-free welds. This will be achieved through welding experiments using various filler alloys and pre and post-weld heating during laser welding, laser-arc hybrid welding and linear friction welding using various process parameters. As in the past, the welding experiments will be performed at Standard Aero. Inc. Winnipeg, and NRC Aerospace Manufacturing Technology Centre, Montreal. Weld cracking and microstructures of the welds will be evaluated, by state-of-the-art microstructure characterization facilities available in applicant's laboratory, to determine the role of process parameters and filler alloy composition on quality of welds. Process parameters and filler alloy compositions will then be optimized through numerical modeling, and the developed model will be validated by further experimentation. It is planned to train 2 M.Sc. and 2 PhD students through the proposed research. This research will help develop welding procedures for Ni and Ti aluminide based emerging aero-turbine materials, and help enhance Canadian Aerospace companies' competitive position in the world markets.