|About this Abstract
||10th International Symposium on Superalloy 718 and Derivatives (2023)
||Superalloy 718 and Derivatives
||Design of Graded Transition Interlayer for Joining Inconel 740H Superalloy with P91 Steel using Wire-arc Additive Manufacturing
||Soumya Sridar, Xin Wang, Mitra Shabani, Michael Klecka, Wei Xiong
|On-Site Speaker (Planned)
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.
||Definite: At-meeting proceedings