2024/08/29 by Kuball, Alexander, Gross, Oliver, Bochtler, Benedikt +2
#600 Technik #Medizin #angewandte Wissenschaften::660 Chemische Verfahrenstechnik::660 Chemische Verfahrenstechnik #differential scanning calorimetry #glass forming ability #high-energy X-ray diffraction #metallic glasses #nucleation and growth #viscosity
paper · doi:10.14279/depositonce-21248
Recently, several families of metallic glasses containing sulphur as alloying element were discovered. In most cases a minor addition of sulphur acts to improve the glass-forming ability of similar alloy compositions that are S-free and leads to bulk vitrification. The role of sulphur in the bulk glass formation is of interest to supplement the universal picture of the process of glass formation. In this work, the focus is on the high S-containing bulk metallic glass Pd31Ni42S27 composition. The molar heat capacity and the viscosity of the undercooled liquid phase of this glass-former are determined and used in combination with continuous and isothermal calorimetric crystallization experiments to quantify the origin of glass formation in this system. The results include in-situ high energy synchrotron X-ray experiments to reveal the crystallization sequences. The glass formation is discussed in terms of the thermodynamic and kinetic contributions. Glass formation is limited by a very fragile kinetic behavior (D* = 8.5) and a high driving force for crystallization reflected by a high entropy of fusion. However, a high interfacial energy between the liquid and the crystalline solid seems to favor it.