Journal Article

PUBDB-2026-01080

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Characterization of the as-cast microstructure, precipitates stability and corrosion resistance of Alloy 718 modified with ex-situ WC nanoparticles

Rakoczy, Ł. (Corresponding author) ; Grudzień-Rakoczy, M. ; Cygan, R. ; Cios, G.Extern* ; Dudziak, T. ; Schell, N.HZG*Hereon* ; Kargul, T. ; Madej, M. ; Cempura, G. ; Rząd, E. ; Kozień, D. ; Chulist, R.Extern* ; Hayashi, S.

2026
Elsevier Lausanne

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Please use a persistent id in citations: doi:10.1016/j.jallcom.2026.187401  doi:10.3204/PUBDB-2026-01080

Abstract: The extension of service life of Ni-based superalloys requires repair materials capable of operating in wear andcorrosive environments, where conventional filler alloys often lack sufficient robustness. This work evaluatesAlloy 718 reinforced with WC nanoparticles as candidates for such applications. Ex-situ composites containing1.25–5.0% WC were produced by suction casting, and their microstructure, phase composition, tribological andcorrosion behavior were characterized. A dendritic structure consisting of a γ-matrix was observed in all variants.In the unreinforced alloy, segregation to interdendritic regions led to precipitation (Nb,Mo)C carbides and Lavesphase. Synchrotron-based analyses, coupled with electron microscopy, confirmed partial dissolution of WCduring solidification, leading to complex (Nb,Mo,W)C carbides and a marked reduction in the Laves phase. Steamoxidation at 704 ◦C for 1000 h showed that all WC-modified variants exhibited lower mass gain compared withAlloy 718. Exposure in Ar+ 0.25% SO₂ revealed that increasing WC content suppressed Ni₃S₂ formation andreduced mass gain to 1.144 mg⋅cm⁻² at 5% WC. Hardness increased from 198HV10 to 221HV10 with 5% WC,accompanied by a modest improvement in dry-sliding wear resistance. These results demonstrate that WCreinforcedAlloy 718 offer enhanced environmental resistance and improved mechanical response, makingthem promising repair materials for Ni-based superalloys.

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Contributing Institute(s):

1. DOOR-User (DOOR ; HAS-User)
2. Helmholtz-Zentrum Hereon (Hereon)

Research Program(s):

1. 6G3 - PETRA III (DESY) (POF4-6G3) (POF4-6G3)

Experiment(s):

1. PETRA Beamline P07 (PETRA III)

Appears in the scientific report 2026

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Database coverage:
; ; ; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; Ebsco Academic Search ; Essential Science Indicators ; IF >= 5 ; JCR ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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