Mechanical properties and devitrification behavior of Cu-Zr-Ti-NM (NM-noble metals) bulk glass-forming alloys

Research output: Contribution to conferencePaperpeer-review

Abstract

The present work is devoted to an investigation of the formation kinetics, stability and homogeneity area of the nanoscale icosahedral phase formed on heating in the Cu-Zr-Ti-NM system alloys. The mechanical properties, glass-forming ability, supercooled liquid region and devitrification behaviour of the Cu-Zr-Ti-NM (NM= Pd, Ag, Au and Pt) bulk glass formers were studied. The bulk glassy alloys of diameter 2 mm were formed in the Cu55Zr 30Ti10Pd5 and Cu55Zr 30Ti10Ag5 alloys while Cu55Zr 30Ti10Au5 bulk alloy showed mixed glassy and crystalline structure. No glassy phase was formed in the Cu55Zr 30Ti10Pt5 bulk alloy whereas the glassy phase was formed in all of the ribbon samples prepared by rapid solidification. The studied alloys except for the Pt-bearing one have slightly increased ultimate compressive fracture strength and yield strength values compared to ternary Cu60Zr30Ti10 glassy alloy. At the same time Pd and Au addition significantly expand the supercooled liquid region of Cu-Zr-Ti glassy alloy and increase Young's modulus. A nanoicosahedral phase is primarily formed in the Cu55Zr30Ti10(Pd,Au)5 glassy alloys in the initial stage of the devitrification process by nucleation and 3-dimensional diffusion controlled growth. Nearly the same quasilattice constant obtained in the Cu55Zr30Ti10(Pd,Au) 5 alloys illustrates the same type of the icosahedral phase in these alloys. However, no icosahedral phase was found in the Cu55Zr 30Ti10(Ag,Pt)5 alloys. The Cu-Zr-Ti-Pd icosahedral phase is not a Cu-rich part of the compositional homogeneity area of the Zr-Cu-Pd one. Nanoscale icosahedral phase has chemical composition close to that of the alloy composition. The possibility for the Cu-Zr-Ti-Pd icosahedral phase of being a Cu-rich part of the compositional homogeneity area of the Zr-Cu-Pd one is ruled out. Moreover, Ti is found to be important element stabilizing quasicrystalline phase in the Cu-Zr-Ti-Pd alloys. Formation criteria for Cu- and Zr/Hf-based icosahedral phases are discussed based on quasilattice constant to average atomic diameter ratio. Deviation from this criterion leads to destabilization of the icosahedral phase.

Original languageEnglish
Pages13-20
Number of pages8
Publication statusPublished - 2006 Dec 1
Event135th TMS Annual Meeting, 2006 - San Antonio, TX, United States
Duration: 2006 Mar 122006 Mar 16

Other

Other135th TMS Annual Meeting, 2006
Country/TerritoryUnited States
CitySan Antonio, TX
Period06/3/1206/3/16

Keywords

  • Bulk metallic glass
  • Nanoscale icosahedral phase

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanics of Materials
  • Metals and Alloys

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