Superalloys 2021: Wednesday Part IV - Alloy Development and Component Manufacture & Repair
Program Organizers: Sammy Tin, University of Arizona; Christopher O'Brien, ATI Specialty Materials; Justin Clews, Pratt & Whitney; Jonathan Cormier, ENSMA - Institut Pprime - UPR CNRS 3346; Qiang Feng, University of Science and Technology Beijing; Mark Hardy, Rolls-Royce Plc; John Marcin, Collins Aerospace; Akane Suzuki, GE Aerospace Research

Wednesday 4:10 PM
September 15, 2021
Room: Live Session Room
Location: Virtual Event

Session Chair: Sammy Tin, University of Arizona; Mark Hardy, Rolls-Royce Plc

4:10 PM
On the Influence of Alloy Chemistry and Processing Conditions on Additive Manufacturability of Ni-based Superalloys: Joseph Ghoussoub¹; Yuanbo Tang¹; Chinnapat Panwisawas¹; Andre Nemeth²; Roger Reed¹; ¹University of Oxford; ²OxMet Technologies Ltd.
    Additive manufacturing trials are carried out on two new nickel-based superalloys designed specifically for this processing method. Their performance—with emphasis on their capability to resist cracking—is assessed by comparing with the two legacy alloys IN939 and CM247LC. The two new alloys are found to have demonstrably superior printability. Thermophysical testing and quantitative characterization, particularly via stereology, are used to help rationalize the physical basis of the improved manufacturability displayed.

4:35 PM
Microstructure and Material Properties of Alloy 718/713LC Joints Using Orbital Friction Welding: Bjoern Hinze¹; ¹Rolls-Royce Deutschland Ltd & Co KG
    This work demonstrates on flat test specimens that orbital friction welding is a suitable process to join a typical disk alloy 718 and a typical blade alloy 713LC. The capability to join nickel-based blades on disks enables the manufacture of blisks instead of the typically used bladed disks. Blisks have the potential to save weight within an aero engine. Orbital friction welding is an alternative process to linear friction welding to enable blade and disk joints. The advantage of orbital friction welding is that the movement is homogenous and the amplitude (or eccentricity) is smaller compared to linear friction welding. This allows joints in areas which are geometrically challenging and impossible to join for linear friction welding. Due to the solid state joining process, there is basically no material mixing within the weld, but within both alloys recrystallization can be seen near the weld line. The result is a fine grained microstructure within both alloys adjacent to the bond line. While this means only a small microstructural change for alloy 718, it is a major microstructural change for the cast coarse grain alloy 713LC. Consequently, the mechanical properties are changed compared to the base material due to the friction welding process. The microstructural changes of orbital friction welding and their influence on the material properties are presented within this work.

5:00 PM
Enhancing the Efficiency and Surface Integrity of Chemical Cleaning during Repair of Ni-base Superalloy Rotating Disks: Eric Huron¹; Nicole Tibbetts¹; Zeynep Bolukoglu¹; Thomas Webster¹; ¹GE Aircraft Engines
    The rotating turbine disks, spools, and seals in the hot section of gas turbine engines are typically made of Nickel-base superalloys. These components operate at high temperatures resulting in dirt accumulation, oxidation, and hot corrosion, and must be cleaned during overhaul to enable inspection and repair. It was found that the typical cleaning solutions used may dissolve the fine carbides present in some superalloys with potential impact on Low Cycle Fatigue (LCF), but that prior shot peening can mitigate this effect. It was also found that, for the highest operating temperatures, grain boundary oxidation may occur in some superalloys and the resultant very fine grain boundary oxides near the surface may be removed by the cleaning process with potential impact on LCF, but that post-cleaning shot peening can address this effect. Studies also showed that more aggressive cleaning solutions may be possible but their impacts on surface condition must be carefully assessed. Finally, it was shown that ultrasonic energy can improve the productivity of the cleaning solutions but must be introduced with proper care to prevent unintended resonance vibration risk to the part.

5:25 PM Question and Answer Period

5:50 PM Concluding Comments