Superalloys 2021: Wednesday Part III - Additive
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 1:30 PM
September 15, 2021
Room: Live Session Room
Location: Virtual Event
Session Chair: Andrew Wessman, University of Arizona; Pete Kantzos, Honeywell Aerospace
1:30 PM Cancelled
Novel Approach for Suppressing of Hot Cracking via Magneto-fluid Dynamic Modification of the Laser-induced Marangoni Convection: André Seidel1; Luise Degener1; Jakob Schneider1; Frank Brueckner1; Eckhard Beyer1; Christoph Leyens1; 1Technical Univ Dresden & Fraunhofer IWS
The occurrence of hot cracking is a significant problem during welding processing of highly heat resistant nickel-base superalloys. Hot cracking is most often associated with liquid films that are present along grain boundaries in the fusion zone and the partially melted zone and can only be suppressed to a very limited extent. The latter is the case despite remarkable studies and analyses of the phenomenon. In this work, a new approach is presented which intends the suppression of hot cracking by using a non-contact method to influence the solidification process. It is based on the idea of a modification of the laser-induced melt pool convection (Marangoni convection) using customized magnetic fields. As a consequence, special system technology is derived on the basis of theoretical considerations while the effectiveness to be expected is estimated on the basis of the information available in the literature. The implemented system technology is described in detail. The focus of this description is on the magnetic flux density distribution or the temporal change, respectively, with respect to the laser-induced melt pool. The presented experimental results provide a comparative view of samples welded with and without the influence of a magnetic field while a significant difference is evident. The outlook of this work describes key data of a test stand specially developed for examining the identified topic in in-depth investigations.
1:55 PM
3D Characterization of the Columnar-to-Equiaxed Transition in Additively Manufactured Inconel 718: Andrew Polonsky1; Narendran Raghavan2; McLean Echlin1; Michael Kirka2; Ryan Dehoff2; Tresa Pollock1; 1University of California, Santa Barbara; 2Oak Ridge National Laboratory
Additive manufacturing (AM) provides enormous processing flexibility, enabling novel part geometries and optimized designs. Access to a local heat source further permits the potential for local microstructure control on the scale of individual melt pools, which can enable local control of part properties. In order to design tailored processing strategies for target microstructures, models predicting the columnar-to-equiaxed transition must be extended to the high solidification velocities and complex thermal histories present in AM. Here, we combine 3D characterization with advanced modeling techniques to develop a more complete understanding of the solidification process and evolution of microstructure during electron beam melting (EBM) of Inconel 718. Full calibration of existing microstructure prediction models demonstrates the differences between AM processes and more conventional welding techniques, underlying the need for accurate determination of key parameters that can only be measured directly in 3D. The ability to combine multisensor data in a consistent 3D framework via data fusion algorithms is essential to fully leverage these advanced characterization approaches. Thermal modeling provides insight on microstructure development within isolated solidification events and demonstrates the role of Marangoni effects on controlling solidification behavior.
2:20 PM
Microstructure and Mechanical Properties of Additively Manufactured Rene 65: Andrew Wessman1; Laura Dial2; Jonathan Cormier3; Kelsey Rainey4; Sammy Tin1; Dhruv Tiparti5; Florence Hamon3; 1University of Arizona; 2GE Global Research; 3Institut Pprime; 4GE Additive; 5Illinois Institute of Technology
Additive manufacturing has enabled the production of highly complex designs that are not producible using traditional manufacturing techniques. While superalloys such as IN718 have been used in these processes for the manufacture of turbine engine structural components, applications requiring higher service temperatures necessitate the development of alloys with increased capability. Rene 65 was developed as a cast-and-wrought alloy with increased capability relative to wrought IN718, and characteristics of that alloy, including temperature stability and thermal crack-resistance, made Rene 65 an appealing candidate to withstand the extreme temperature gradients that are characteristic of direct metal laser melting (DMLM) additive manufacturing. The as-built DMLM microstructure is very different from as-forged microstructure, and this work will examine the effect of heat treatments both below (sub-) and above (super-) the gamma prime (ã′) solvus on the grain and precipitate structure of AM Rene 65 material. Tensile, fatigue and creep behavior of the alloy in these different heat treatment conditions is reported. Relative to AM IN718, AM Rene 65 shows the desired improvement in temperature capability analogous to that in the cast and wrought versions of the alloys. Differences in the balance of properties are noted between AM Rene 65 and cast and wrought Rene 65, which are attributable to the differences in grain size and precipitate distribution and which may provide benefits for certain applications.
2:45 PM Question and Answer Period