Development of a New Alumina-Forming Crack-Resistant High-γ′ Fraction Ni-Base Superalloy for Additive Manufacturing

Zhou, Ning; Dicus, Austin D.; Forsik, Stéphane A. J.; Wang, Tao; Colombo, Gian; Epler, Mario E.

doi:10.1007/978-3-030-51834-9_102

Cited by 17 publications

(13 citation statements)

References 30 publications

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“…The factors conferring CM247LC with increased creep life relative to the novel alloy variants are likely (i) the greater γ volume fraction [36,37] as well as (ii) the substantially higher C and B contents [38,39,40]. Good agreement was observed between the creep performance of L-PBF produced CM247LC -tested parallel to the build direction -reported here and in the literature [12,13,41]. The superiority of CM247LC was reduced under conditions of higher stress and lower temperatures where APB shearing is the dominant deformation mechanism, as opposed to the low stress and high temperature conditions where dislocation climb bypass dominates [42,43].…”

Section: Creep Resistancesupporting

confidence: 72%

“…If the tensile axis of the mechanical testing performed had instead been perpendicular to the build direction, the load state on the internal cracks of CM247LC would be Mode I -tensile stress normal to the crack plane -which would likely increase the detrimental effect of the processing induced defects [44]. Figure 6: Plot of the stress level vs Larson-Miller parameter for the compositions creep tested with the build directon as the tensile axis with data from the literature [12,13,41] superimposed on the results of this study.…”

Section: Creep Resistancementioning

confidence: 99%

“…There is evidence that this second approach has merit [11]. Alloy design approaches are emerging for this purpose [12,13,14]. Nevertheless, work of the type reported here is needed to assess the effectiveness of the alloy design strategies.…”

Section: Introductionmentioning

confidence: 99%

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A New Class of Alumina-Forming Superalloy for 3D Printing

Klupś¹,

Dick-Cleland²,

Rankin³

et al. 2021

Preprint

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A new class of crack-resistant nickel-based superalloy containing high γ fraction is studied for the laser-powder bed fusion (L-PBF) process. The effects of the (Nb+Ta)/Al ratio is emphasised, a strategy that is shown to confer excellent low-temperature strength whilst maintaining oxidation resistance at high temperatures via stable alumina scale formation. The processability of the new alloys is characterised with respect to defect assessment by micro-focus x-ray computed tomography; use is made of a prototype turbine blade geometry and the heritage alloy CM247LC as a benchmark. In all cases, some processing-related porosity is present in thin wall sections such as the trailing edge, but this can be avoided by judicious processing. The cracking seen in CM247LC -in solid-state, liquation and solidification forms -is avoided. A novel sub-solvus heat treatment strategy is proposed which takes advantage of AM not requiring solutioning; super-solvus heat treatment is inappropriate since it embrittles the material by deterioration of the texture and coarsening of grain boundary carbides. The tensile strength of the new superalloy is greatest when the Nb+Ta content is highest and exceeds that of CM247LC up to ∼900 • C. The oxidation resistance is best when Al content is highest, and oxidation-assisted cracking resistance maximized when the (Nb+Ta)/Al ratio is balanced. In all cases these are equivalent or superior to that of CM247LC. Nevertheless, the creep resistance of the new alloys is somewhat inferior to that of CM247LC for which the γ , C, and B contents are higher; this implies a processing/property trade-off which requires further clarification.

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Section: Creep Resistancesupporting

confidence: 72%

Section: Creep Resistancementioning

confidence: 99%

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A New Class of Alumina-Forming Superalloy for 3D Printing

Klupś¹,

Dick-Cleland²,

Rankin³

et al. 2021

Preprint

View full text Add to dashboard Cite

show abstract

“…ExpAM-mod [41] and MAD542 [42] sit in the good additive manufacturability zone based on processinduced porosity (Figure 6), cooling rate (Figure 7) and mass loss results (Figure 8). This emphasises that new alloys are needed for the successful additive manufacturability [17,40] rationalised by thermal-fluid flow processing maps linked between compostion and process characteristics.…”

Section: Volatile Mass Loss / Vapourisationmentioning

confidence: 99%

“…But the physical picture clarified in this study will help to understand the effects of relevant phenomena in AM. Above all, from the CFD calculation and the thermo-physical property estimation, it can be noticed that new nickel-based superalloys designed for AM such as ABD-850AM [40], ABD-900AM [40], ExpAM [41],…”

Section: Volatile Mass Loss / Vapourisationmentioning

confidence: 99%