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Title: Effects of rare earth yttrium on microstructure and properties of Ni–16Mo–7Cr–4Fe nickel-based superalloy

Effects of rare earth yttrium on microstructure of Ni–16Mo–7Cr–4Fe alloy were examined by optical microscopy, scanning electron microscopy, transmission electron microscopy and X-ray fluorescence. M{sub 6}C phase was observed in the alloys with and without yttrium addition, and Ni{sub 17}Y{sub 2} phase existed in the alloys containing 0.05–0.43 wt.% yttrium simultaneously. The amount of Ni{sub 17}Y{sub 2} phase increased as yttrium concentration increased. When the concentration of yttrium increased to 0.43 wt.%, some multi-precipitated phase regions appeared in the form of large amount of coarse Ni{sub 3}Y phase surrounded by M{sub 6}C phase and γ phase in the alloy. Influences of rare earth yttrium on high temperature static oxidation and mechanical properties of Ni–16Mo–7Cr–4Fe alloy were also investigated. The alloy containing 0.05 wt.% yttrium showed the best oxidation resistance and mechanical properties simultaneously. The adequate concentration of yttrium at grain boundary and in the solid-solution (γ phase) and the adhesion enhancement of the outer oxidation scale to the substrate are key factors for the improvements in the mechanical properties and oxidation resistance respectively. - Highlights: • When the content of yttrium reaches to 0.43%, some multiphase regions appear. • When the content of yttrium reaches to 0.43%, some Ni{sub 17}Y{submore » 2} chains appear. • The morphology of M{sub 6}C changes with increasing concentration of yttrium. • The Ni–16Mo–7Cr–4Fe alloy with 0.05% yttrium performs the best mechanical property. • The Ni–16Mo–7Cr–4Fe alloy with 0.05% yttrium performs the best oxidation resistance.« less
Authors:
 [1] ;  [2] ; ; ;  [1] ;  [2] ;  [1]
  1. Shanghai Institute of Applied Physics, China Academy of Sciences, 2019 Jialuo Road, Shanghai 201800 (China)
  2. Shanghai Synchrotron Radiation Facility (SSRF), Shanghai Institute of Applied Physics, Chinese Academy of Sciences, 239 Zhangheng Road, Shanghai 201204 (China)
Publication Date:
OSTI Identifier:
22403546
Resource Type:
Journal Article
Resource Relation:
Journal Name: Materials Characterization; Journal Volume: 95; Other Information: Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; CHROMIUM ALLOYS; CONCENTRATION RATIO; GRAIN BOUNDARIES; IRON ALLOYS; MECHANICAL PROPERTIES; MOLYBDENUM BASE ALLOYS; MORPHOLOGY; NICKEL; NICKEL ALLOYS; OPTICAL MICROSCOPY; OXIDATION; RARE EARTHS; SCANNING ELECTRON MICROSCOPY; SOLID SOLUTIONS; SUBSTRATES; TRANSMISSION ELECTRON MICROSCOPY; YTTRIUM; YTTRIUM ADDITIONS