Thermodynamical analysis of the glass-forming ability of bulk metallic glasses

Abstract

The glass-forming ability (GFA) of bulk metallic glasses (BMGs) has been analyzed on the basis of the thermodynamic parameters such as the specific heat difference δCpm between the undercooled liquid and corresponding equilibrium solid phase at the melting temperature Tm, entropy of fusion δSm, and the residual entropy δS R and characteristic temperatures, such as the Kauzmann temperature TK, glass transition temperature Tg, and the melting temperature Tm. The entire study is performed by analyzing the variation of critical cooling rate Rc with TK/T m, δCpm/δSm, (T g - TK)/Tm and δSR/ δSm for a large number of BMGs. The variation of T K/Tm and δSR/δSm with δCpm/δSm has also been studied for BMGs. It has been found that materials having large δCp m/δSm exhibit large TK/Tm and suchmaterials require low Rc for the glass formation. At the same time, it has also been found thatmaterials having large TK/T m exhibit low δSR/δSm and suchmaterials need a low Rc for the glass formation. Attempt has also beenmade to correlate Rc with TK/Tm, δCpm/δSm, (Tg - T K)/Tm and δSR/δSm for BMGs. © Akadémiai Kiadó, Budapest, Hungary 2011.