In the present study we investigate the phase formation and the thermal stability of Cu50Zr50 - xTix (0 ≤ x ≤ 10) and (Cu0.5Zr0.5)100 - xAlx glass-forming alloys. Parameters indicating the glass-forming ability (GFA) are calculated from isochronal and isothermal calorimetric experiments. A high Ti content in the Cu-Zr-Ti alloys causes the precipitation of a metastable ternary Laves phase (C15), which does not form in Cu-Zr-Al. Accompanied with it is a significant drop in the activation energy of crystallization. Also the supercooled liquid region (ΔTx = Tx - Tg), the reduced glass transition temperature (Trg = Tg/Tliq), and the γ parameter (γ = Tx/(Tg + Tliq)) (Tx: crystallization temperature, Tg: glass transition temperature and Tliq: liquidus temperature) are sensitive to the change in the crystallization sequence. The fragility values calculated are believed to overestimate the GFA of the investigated alloys. Careful selection of the alloy composition enables the targeted precipitation of different crystalline phases.
Bibliographical noteFunding Information:
The authors thank B. Bartusch, S. Donath, M. Frey and H. Schulze for technical assistance, and J. Bednarcik, H. Ehrenberg, K. Nikolowski, N. Mattern, S. Scudino, M. Stoica, and S. Venkataraman for stimulating discussions. Financial support provided by the EU within the framework of the research and training network on Ductile BMG Composites (MRTN-CT-2003-504692) and through the Global Research Laboratory Program of the Korean Ministry of Education, Science and Technology is gratefully acknowledged.
S.P. furthermore acknowledges financial support granted by the program “Promotionsförderung des Cusanuswerks”.
All Science Journal Classification (ASJC) codes
- Mechanics of Materials
- Mechanical Engineering
- Metals and Alloys
- Materials Chemistry