論文

2019年

NOVEL MICROSTRUCTURE DESIGN APPROACH USING TCP AND GCP IN NI-CR-M TERNARY SYSTEMS BASED ON PHASE DIAGRAM STUDY AT ELEVATED TEMPERATURE

JOINT EPRI - 123HIMAT INTERNATIONAL CONFERENCE ON ADVANCES IN HIGH-TEMPERATURE MATERIALS, 2019
  • Ryota Nagashima
  • ,
  • Ryosuke Yamagata
  • ,
  • Hirotoyo Nakashima
  • ,
  • Satoru Kobayashi
  • ,
  • Masao Takeyama

開始ページ
1436
終了ページ
1445
記述言語
英語
掲載種別
研究論文(国際会議プロシーディングス)
出版者・発行元
ASM INTERNATIONAL

Strengthening of Ni-based superalloys is in principle designed using GCP (Geometrically Close-packed phase) of Ni3Al-gamma' (Ll(2)). However, game-changing microstructural design principle without relying on gamma' phase will be needed for further development of the alloys. We are currently constructing a novel microstructure design principle, using thermodynamically stable TCP (Topologically Close -packed phase) for grain boundaries, together with GCP other than gamma' phase for grain interiors, based on grain boundary precipitation strengthening (GBPS) mechanism. One of the promising systems is Ni-Cr-Mo ternary system, where TCP of NiMo (oP112) phases, mu (hR13) and P (oP56), together with GCP of Ni3Mo (oP8) and Ni2Cr (oP6) exists. In this study, thus, phase equilibria among Al (fcc)/TCP/GCP phases in Ni-Cr-Mo and Ni-Cr-W systems have been examined at temperature range from 973 K to 1073 K, based on experiment and calculation. In Ni-Cr-Mo system, Ni-2(Cr, Mo) with oP6 Pearson symbol, which is stable at about 873 K in Ni-Cr binary system, is formed to exist even at 1073 K. oP6 phase is coherently formed in Al matrix with a crystallographic orientation of {110}(A1) // (100)(oP6), <001 >(A1) // [010](oP6), indicating GCP at composition range around Ni-15Cr-15Mo as island. In Mo-rich region there is A1/NiMo/oP6 three-phase coexisting region, whereas another three-phase coexisting region of A1/P/oP6 exists in Cr-rich region. Based on vertical section, it is possible to design microstructure with TCP at grain boundaries, together with oP6 phase within grain interiors by two-step heat treatment.

リンク情報
Web of Science
https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=JSTA_CEL&SrcApp=J_Gate_JST&DestLinkType=FullRecord&KeyUT=WOS:000505657800146&DestApp=WOS_CPL
ID情報
  • Web of Science ID : WOS:000505657800146

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