On the fragility and equilibrium phases of metallic glass forming alloys Public Deposited

http://ir.library.oregonstate.edu/concern/graduate_thesis_or_dissertations/zc77st54n

Descriptions

Attribute NameValues
Creator
Abstract or Summary
  • The heating rate dependence of the glass transition temperature of the Ni₆₅Nb₃₅, Ni₆₀Nb₃₅Sn₅, Ni₅₉.₃₅Nb₃₄.₄₅Sn62, Ni₆₀(Nb₄₀Ta₆₀)₃₄Sn₆, and Ni₅₇Fe₃Nb₃₅Sn₅ metallic glass forming alloys was investigated with a differential scanning calorimeter (DSC). The inverse heating rate for each DSC experiment was plotted versus inverse temperature and a Vogel-Fulcher- Tamman (VFT) type relation was fit to the data in the plot. The fragilities of the alloys were characterized with the steepness index, m, the fragility parameter D*, and the VFT temperature, T₀ which are the fit parameters from the VFT relation. It was found that for the binary alloy D* = 6.2, for the ternary alloys D* = 11.0, and that for both the quaternary alloys D* was about 16. For these alloys, D* increases linearly as the number of components in the alloy increases. The fragilities of Zr₄₅.₃₈Ti₉.₆₂Cu₈.₇₅Ni₁₀Be₂₆.₂₅, Zr₄₄Ti₁₁Cu₁₀Ni₁₀Be₂₅, Zr₄₂.₆₃Ti₁₂.₃₇Cu₁₁.₂₅Ni₁₀Be₂₃.₇₅, Zr₄₁.₂Ti₁₃.₈Cu₁₂.₅Ni₁₀Be₂₂.₅, Zr₃₉.₈₈Ti₁₅.₁₂Cu₁₃.₇₇Ni₉.₉₈Be₂₁.₂₅, Zr₃₈.₅Ti₁₆.₅Cu₁₅.₂₅Ni₉.₇₅Be₂₀, and Zr₄₆.₇₅Ti₈.₂₅Cu₇.₅Ni₁₀Be₂₇.₅ were also characterized by the same method. It was found that D* increases with increasing concentration of Ti and Cu and decreasing concentration of Zr and Be. The crystalline equilibrium phases of the Zr₅₇Cu₁₅.₄Ni₁₂.₆AI₁₀Nb₅ (Vit 106) bulk metallic glass-forming alloy were determined with electron microprobe analysis (EMPA) and X-ray diffraction (XRD). Five equilibrium phases were found. XRD, EMPA and cluster analysis show that those phases are Zr₂Ni, Zr₂Cu, ZrCu, Zr₃Al₂, and Zr₄AI₃. All the equilibrium phases, derived from the binary intermetallic compounds, contain the other elements as solutes. In Zr₂Ni and Zr₂Cu, Ni substitutes Cu and vice versa. In ZrCu, Ni and Al substitute the Cu. In Zr₃Al₂ and Zr₄AI₃, Nb substitutes Zr, and Al is substituted by Cu and Ni. This study shows that the additions of 10% Al and 5% Nb are optimum concentrations in the composition space to retard the nucleation and growth of these equilibrium phases when the melt is undercooled.
License
Resource Type
Date Available
Date Issued
Degree Level
Degree Name
Degree Field
Degree Grantor
Commencement Year
Advisor
Non-Academic Affiliation
Subject
Rights Statement
Peer Reviewed
Language
Digitization Specifications
  • File scanned at 300 ppi (Monochrome, 256 Grayscale) using Capture Perfect 3.0.82 on a Canon DR-9080C in PDF format. CVista PdfCompressor 4.0 was used for pdf compression and textual OCR.
Replaces
Additional Information
  • description.provenance : Approved for entry into archive by Patricia Black(patricia.black@oregonstate.edu) on 2012-07-09T18:28:54Z (GMT) No. of bitstreams: 1ShadowspeakerLudiA2004.pdf: 542011 bytes, checksum: 09897df8ae686812838057a5beff6077 (MD5)
  • description.provenance : Submitted by Kevin Martin (martikev@onid.orst.edu) on 2012-06-26T18:56:38ZNo. of bitstreams: 1ShadowspeakerLudiA2004.pdf: 542011 bytes, checksum: 09897df8ae686812838057a5beff6077 (MD5)
  • description.provenance : Approved for entry into archive by Patricia Black(patricia.black@oregonstate.edu) on 2012-07-09T18:30:18Z (GMT) No. of bitstreams: 1ShadowspeakerLudiA2004.pdf: 542011 bytes, checksum: 09897df8ae686812838057a5beff6077 (MD5)
  • description.provenance : Made available in DSpace on 2012-07-09T18:30:18Z (GMT). No. of bitstreams: 1ShadowspeakerLudiA2004.pdf: 542011 bytes, checksum: 09897df8ae686812838057a5beff6077 (MD5) Previous issue date: 2003-08-26

Relationships

Parents:

This work has no parents.

Last modified

Downloadable Content

Download PDF

Items