Effect of Sm on Crystallization Kinetics of Cu-Zr-Al Metallic Glasses

Sıkan F., Polat G., Kalay I., Kalay Y. E.

THERMOCHIMICA ACTA, cilt.683, 2020 (SCI-Expanded) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 683
  • Basım Tarihi: 2020
  • Doi Numarası: 10.1016/j.tca.2019.178439
  • Dergi Adı: THERMOCHIMICA ACTA
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Aerospace Database, Analytical Abstracts, Aquatic Science & Fisheries Abstracts (ASFA), Biotechnology Research Abstracts, Chemical Abstracts Core, Chimica, Communication Abstracts, Compendex, INSPEC, Metadex, Civil Engineering Abstracts
  • Anahtar Kelimeler: Metallic glasses, Crystallization, Kinetics, SUPERCOOLED LIQUID REGION, PHASE-SEPARATION, MECHANICAL-BEHAVIOR, MICROSTRUCTURE, PLASTICITY, DIFFUSION, ALLOYS
  • Orta Doğu Teknik Üniversitesi Adresli: Evet

Özet

The effect of Sm micro-alloying on non-isothermal and isothermal crystallization kinetics of (Zr50Cu40Al10)(100-x)Sm-x (x = 0, 2, 4 at. % Sm) alloys were investigated using differential scanning calorimetry (DSC), transmission electron microscopy (TEM), and X-ray diffraction (XRD). Crystallization activation energies for each composition were calculated in non-isothermal conditions using Kissinger and Ozawa methods and in isothermal conditions using Johnson-Mehl-Avrami model. XRD analysis showed that crystallization product Cu10Zr7 changes to Cu2Sm with Sm presence in isothermal conditions. Both isothermal and isochronal calculations yield that the energy barrier for crystallization has increased with Sm addition. On the other hand, crystallization point drops to lower temperature at the expense of an increase in the pre-exponential factor. The Avrami exponents for all compositions were found to be below 2.5, indicating that crystallization was governed by a diffusion-controlled three-dimensional growth with a decreasing nucleation rate. The apparent increase in crystallization activation energies with increasing Sm content can be one of the affecting factors for commonly held idea of increased glass forming ability for rare-earth containing Zr-based metallic glasses.