Scanning electron microscopy and atom probe tomography characterization of laser powder bed fusion precipitation strengthening nickel-based superalloy
Journal article, 2023

Atom probe tomography (APT) was utilized to supplement scanning electron microscopy (SEM) characterization of a precipitation strengthening nickel-based superalloy, Alloy 247LC, processed by laser powder bed fusion (L-PBF). It was observed that the material in the as-built condition had a relatively high strength. Using both SEM and APT, it was concluded that the high strength was not attributed to the typical precipitation strengthening effect of γ’. In the absence of γ’ it could be reasonably inferred that the numerous black dots observed in the cells/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 in the absence of precipitated γ’. Even though γ’ was not precipitated, the APT analysis displayed a nanometer scale partitioning of Cr that could be contributing to the strengthening. After heat-treatment, γ’ was precipitated and it demonstrated the expected high strengthening behavior. Al, Ta and Ti partitioned to γ’. The strong partitioning of Ta in γ’ is indicative that the element, together with Al and Ti, was contributing to the strain-age cracking occurring during heat-treatment. Cr, Mo and Co partitioned to the matrix γ phase. Hf, Ta, Ti and W were found in the carbides corroborating previous reports that they are MC.

CM247LC

Scanning electron microscopy, gamma prime

Superalloy

Additive manufacturing, atom probe tomography

Author

Olutayo Adegoke

Siemens Energy

Chamara Kumara

University West

FEV Sverige AB

Mattias Thuvander

Chalmers, Physics, Microstructure Physics

Faraz Deirmina

Siemens Energy

Joel Håkan Andersson

University West

Håkan Brodin

Siemens Energy

P. Harlin

University West

Sandvik

Robert Pederson

University West

Micron

0968-4328 (ISSN)

Vol. 171 103472

Subject Categories

Manufacturing, Surface and Joining Technology

Materials Chemistry

Metallurgy and Metallic Materials

DOI

10.1016/j.micron.2023.103472

PubMed

37146362

More information

Latest update

11/2/2023