Scanning electron microscopy and atom probe tomography characterization of laser powder bed fusion precipitation strengthening nickel-based superalloy

Atom probe tomography (APT) was utilized to supplement scanning electron microscopy (SEM) characterizationof a precipitation strengthening nickel-based superalloy, Alloy 247LC, processed by laser powder bed fusion (LPBF). It was observed that the material in the as-built condition had a relatively high strength. Using both SEMand APT, it was concluded that the high strength was not attributed to the typical precipitation strengtheningeffect of γ’. In the absence of γ’ it could be reasonably inferred that the numerous black dots observed in thecells/grains with SEM were dislocations and as such should be contributing significantly to the strengthening.Thus, the current investigation demonstrated that relatively high strengthening can be attained in L-PBF even inthe absence of precipitated γ’. Even though γ’ was not precipitated, the APT analysis displayed a nanometer scalepartitioning of Cr that could be contributing to the strengthening. After heat-treatment, γ’ was precipitated and itdemonstrated the expected high strengthening behavior. Al, Ta and Ti partitioned to γ’. The strong partitioningof Ta in γ’ is indicative that the element, together with Al and Ti, was contributing to the strain-age crackingoccurring during heat-treatment. Cr, Mo and Co partitioned to the matrix γ phase. Hf, Ta, Ti and W were found inthe carbides corroborating previous reports that they are MC.

Kumara, ChamaraHögskolan Väst,Avdelningen för avverkande och additativa tillverkningsprocesser (AAT),FEV Sverige AB, Trollhättan (SWE),KAMPT,University West(Swepub:hv)chku0003 (author)
Thuvander, Mattias,1968Department of Physics, Chalmers University of Technology, Gothenburg (SWE),Chalmers tekniska högskola,Chalmers University of Technology(Swepub:cth)matthu (author)
Deirmina, FarazSiemens Energy, Finspång (SWE),Siemens Energy AB (author)
Andersson, Joel,1981-Högskolan Väst,Avdelningen för svetsteknologi (SV),KAMPT,University West(Swepub:cth)hakaand (author)
Brodin, HåkanSiemens Energy, Finspång (SWE),Siemens Energy AB (author)
Harlin, Peter,1974-Högskolan Väst,Avdelningen för avverkande och additativa tillverkningsprocesser (AAT),Sandvik Additive Manufacturing, Sandviken (SWE),KAMPT,University West,Sandvik Group AB(Swepub:hv)pethar (author)
Pederson, Robert,1973-Högskolan Väst,Avdelningen för avverkande och additativa tillverkningsprocesser (AAT),KAMPT,University West(Swepub:cth)pederson (author)
Siemens Energy, Finspång (SWE)Siemens Energy AB (creator_code:org_t)

By the author/editor: Adegoke, Olutayo; Kumara, Chamara; Thuvander, Matti ...; Deirmina, Faraz; Andersson, Joel, ...; Brodin, Håkan; show more...; Harlin, Peter, 1 ...; Pederson, Robert ...; show less...

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ENGINEERING AND TECHNOLOGY: ENGINEERING AND ...; and Materials Engine ...; and Manufacturing Su ...

NATURAL SCIENCES: NATURAL SCIENCES; and Chemical Science ...; and Materials Chemis ...

ENGINEERING AND TECHNOLOGY: ENGINEERING AND ...; and Materials Engine ...; and Metallurgy and M ...

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