Effects of the microstructure and minor elements on the fracture toughness of Nb-Si alloy

Takuya Okawa, Seiji Miura, Tetsuo Mohri

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


The development of a new high temperature structural material is recently required in various fields. As one of the potential materials, Nb-Si alloys have attracted attention due to their high melting point and low density. A microstructure composed of ductile Nb matrix containing finely dispersed spherical ND5Si3 phase is obtained by the addition of ternary elements such as Au and it is found that such microstructure is effective in improving room temperature toughness. The main purpose of the present study is evaluating fracture toughness of Nb-Si-Au alloys using small specimens and investigating the effects of the microstructure and other minor elements on the fracture toughness. Alloy ingots of Nb-15at.%Si-3at.%Au and Nb-3at.%Au are prepared by arc-melting under Ar atmosphere, followed by heat-treatments at up to 1500°C for 100 hours. Chevron notched specimens with a size of 1.0x2.0x 10mm are subjected to four-point bending tests under a laser confocal microscope for in-situ observation of crack propagation, and the effect of the microstructure and minor elements such as oxygen on the evaluated fracture toughness is investigated on both the Nb/Nb5Si3 alloys and the Nb solid solution (Nbss) alloys.

Original languageEnglish
Title of host publicationIntermetallic-Based Alloys - Science, Technology and Applications
Number of pages5
Publication statusPublished - 2013 Oct 1
Event2012 MRS Fall Meeting - Boston, MA, United States
Duration: 2012 Nov 252012 Nov 30

Publication series

NameMaterials Research Society Symposium Proceedings
ISSN (Print)0272-9172


Other2012 MRS Fall Meeting
Country/TerritoryUnited States
CityBoston, MA

ASJC Scopus subject areas

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


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