About this Abstract |
| Meeting |
10th International Symposium on Superalloy 718 and Derivatives (2023)
|
| Symposium
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Superalloy 718 and Derivatives
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| Presentation Title |
Design of Graded Transition Interlayer for Joining Inconel 740H Superalloy with P91 Steel using Wire-arc Additive Manufacturing |
| Author(s) |
Soumya Sridar, Xin Wang, Mitra Shabani, Michael Klecka, Wei Xiong |
| On-Site Speaker (Planned) |
Soumya Sridar |
| Abstract Scope |
Design of an efficient interlayer is imperative for joining dissimilar materials using additive manufacturing to achieve smooth variation in properties. In this work, two graded transition interlayers were designed using a CALPHAD-based ICME framework (CALPHAD: Calculation of Phase Diagrams; ICME: Integrated Computational Materials Engineering) for joining Inconel 740H superalloy with P91 steel. Successful builds with the designed interlayers (60 and 85 wt.% P91) sandwiched between the constituent materials were fabricated using wire-arc additive manufacturing. The 60 wt.% P91 interlayer was found to exhibit an FCC matrix while the 85 wt.% P91 interlayer had a martensitic matrix. A two-step post-heat treatment consisting of homogenization and aging was designed. The key temperatures for each step were determined supported by CALPHAD-prediction of phase stability diagrams. The 60 wt.% P91 graded interlayer showed no improvement in hardness after aging. This agrees with the CALPHAD model predictions, which showed a lack of γ’ precipitates after aging for this composition. The hardness of 85 wt.% P91 improved considerably after aging with an optimum aging time of 8 hours. In addition, mechanical tests were performed to determine the location of failure as well as tensile properties. The 60% P91 graded interlayer builds failed at the interlayer while the 85% P91 build failed in the pure P91 region. This proves that the post-heat treated 85% P91 is much stronger than the pure P91 and hence, the strategy used in this work is successful for design of interlayers for dissimilar joining. |
| Proceedings Inclusion? |
Definite: At-meeting proceedings |