Alloy 740H Component Manufacturing Development

Barbadillo, John J. de; Baker, Brian; Gollihue, Ronald D.; Patel, Saurabh K.

doi:10.1002/9781119027973.ch22

Cited by 2 publications

(1 citation statement)

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“…MX (M = Ti, Nb; X = C, N) phase will act as pinning particles to avoid excessive grain coarsening during homogenization. It is to be noted that the design targets for the tensile properties were obtained from the ASME Code Case 2702, which certifies Inconel 740H superalloys for service in AUSC power plants in 2011 [16]. The fabrication of Inconel 740H superalloy using WAAM has been explored for the first time in this work.…”

Section: Introductionmentioning

confidence: 99%

Achieving High Strength and Creep Resistance in Inconel 740H Superalloy through Wire-Arc Additive Manufacturing and Thermodynamic-Guided Heat Treatment

Sridar,

Ladinos Pizano,

Klecka

et al. 2023

Materials

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Inconel 740H superalloy is commonly used in advanced ultra-supercritical power plants since it possesses excellent strength and creep resistance. This study investigates the microstructure and mechanical properties of Inconel 740H superalloy fabricated using wire-arc additive manufacturing. The as-printed microstructure consisted of columnar γ grains with the Laves phase and (Nb, Ti)C carbides as secondary phases. The anisotropy in grain structure increased from the bottom to the top regions, while the hardness was highest in the middle portion of the build. To guide the post-heat treatment design, thermodynamic and kinetic simulations were employed to predict the temperature and time. Complete recrystallization with the Laves phase dissolution occurred throughout the build after homogenization at 1200 °C for 2 h. The peak hardness was achieved after aging at 760 °C for 12 h with the M23C6 carbides decorating the grain boundaries and γ’ precipitates in the grain interior. The yield strength (655 MPa) and ductility (29.5%) in the post-heat treated condition exceeded the design targets (620 MPa, 20%). Stress rupture tests at 750 °C showed that the high-temperature performance was at par with the wrought counterparts. The fracture mode after rupture was identified to be intergranular with the presence of grain boundary cavities along with grain boundary sliding.

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Section: Introductionmentioning

confidence: 99%