Alloy design of Nb-Si based high temperature alloys by phase stability control

Seiji Miura, Tatsuichi Tanahashi, Yoshinao Mishima, Tetsuo Mohri

Research output: Chapter in Book/Report/Conference proceedingConference contribution

5 Citations (Scopus)

Abstract

In order to spheroidize α-Nb5Si3 strengthening phase embedded in Nb matrix for attaining a good room temperature toughness of Nb-Si alloy, the authors have proposed a microstructure control technique by combining eutectic and eutectoid reactions. Nb3Si intermetallic compound formed during solidification is a key phase for the microstructure control, but its stability is very sensitive to the alloying elements. Nb 3Si disappears by adding as small as 3 at% of W and Mo, while these elements are very effective for the solid solution strengthening of Nb phase. For a further alloy development, establishment of an alloy design concept based on the control of phase stability of Nb3Si is needed. Similarly to ferrous alloys such as stainless steels where Cr and Ni are added to control the stability of bcc phase and fcc phase, two alloying elements (one is a stabilizing element and the other is a destabilizing element for Nb 3Si phase) are added to a Nb-Si binary master alloy and their microstructure is investigated using SEM. The stabilizing element Ta is found to enlarge the composition area where Nb3Si exists even with the destabilizing element Mo, and it is confirmed that the phase stability concept is useful for designing Nb-Si based alloys.

Original languageEnglish
Title of host publicationPRICM7
PublisherTrans Tech Publications Ltd
Pages444-447
Number of pages4
ISBN (Print)0878492550, 9780878492558
DOIs
Publication statusPublished - 2010
Event7th Pacific Rim International Conference on Advanced Materials and Processing, PRICM-7 - Cairns, QLD, Australia
Duration: 2010 Aug 22010 Aug 6

Publication series

NameMaterials Science Forum
Volume654-656
ISSN (Print)0255-5476
ISSN (Electronic)1662-9752

Other

Other7th Pacific Rim International Conference on Advanced Materials and Processing, PRICM-7
CountryAustralia
CityCairns, QLD
Period10/8/210/8/6

Keywords

  • Microstructure control
  • NbSi
  • Schaeffler's diagram
  • Spheroidization
  • α-NbSi

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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