Influence of Ag and Co additions on glass-forming ability, thermal and mechanical properties of Cu-Zr-Al bulk metallic glasses

Author(s)
B. Escher, U. Kühn, J. Eckert, C. Rentenberger, S. Pauly
Abstract

In this study, the effect different amounts of Ag and Co have on thermal

stability, phase formation and mechanical properties of the

glass-forming alloys (Cu0.5Zr0.5)95−x−yAl5AgxCoy (2≤x≤5 and 0≤y≤2) and Cu47.5−yZr47.5Al5Coy

(0≤y≤2) was investigated, respectively. The addition of Ag increases

the glass-forming ability (GFA) of the alloys by enhancing the stability

of the undercooled melt and by simultaneously reducing the stability of

the B2 CuZr high-temperature phase. Co instead, has the opposite

effect. It leads to an increased thermal stability of the B2 phase, as

well as a decreased stability of the undercooled melt and, consequently,

lowers the GFA of the alloys. Moreover, a metastable big cube phase

precipitates in some alloys stabilized by oxygen, which is introduced

during casting. There is a strong interdependence between the phase

formation and the tendency of the present alloys to vitrify. This

correlation can be captured by the K-parameter (Song et al. 2011 [1])

calculated from the respective transformation temperatures. The plastic

strain of the present ternary, quaternary and quinary alloys reflects

the GFA as well: the higher the tendency to form a glass, the smaller

the plastic strain. Once B2 crystals precipitate in the glass, the

plasticity is enhanced significantly.

Organisation(s)
Physics of Nanostructured Materials
Journal
Materials Science and Engineering A: Structural Materials: Properties, Microstructures and Processing
Volume
673
Pages
90-98
No. of pages
9
ISSN
0921-5093
DOI
https://doi.org/10.1016/j.msea.2016.06.081
Publication date
09-2016
Publication status
Published
Peer reviewed
Yes
Austrian Fields of Science 2012
103018 Materials physics
Keywords
Amorphous materials, Metallic glasses, Mechanical properties, Calorimetry, X-ray diffraction, CRYSTALLIZATION BEHAVIOR, COMPOSITIONAL DEPENDENCE, PHASE-FORMATION, ALLOYS, PLASTICITY, STABILITY, OXYGEN, CU50ZR50, ORIGIN
Portal url
https://ucris.univie.ac.at/portal/en/publications/influence-of-ag-and-co-additions-on-glassforming-ability-thermal-and-mechanical-properties-of-cuzral-bulk-metallic-glasses(7132aa5d-3856-440a-9124-f5b5fa50c948).html