The process of spontaneous vitrification evaluated by calorimetry

• Published in: Journal of the less-common metals 1988-12, Vol.145 (1-2), p.81-88
• Main Authors: Blatter, A., Koch, N., Kambli, U.
• Format: Article
• Language: English
• Subjects: Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Materials science; Metals, semimetals and alloys; Phase diagrams and microstructures developed by solidification and solid-solid phase transformations; Physics; Specific materials
• ISSN: 0022-5088
• DOI: 10.1016/0022-5088(88)90264-0

The Cr 40Ti 60 and Cr 28Fe 8Ti 64 high temperature b.c.c. solid solutions, if properly quenched to room temperature, transform into an amorphous structure on subsequent annealing. Here we report on calorimetric studies of this vitrification process. The specific heat was measured during temperature cycling between 50 °C and 600 °C. In the first heating cycle, the crystal phase undergoes quick stress relaxation and subsequently exhibits the thermal and elastic behaviour of the vitrified state. However, X-ray diffraction still shows predominantly crystalline features which then progressively disappear in the following heating cycles. We conclude that vitrification—with respect to different system variables — evolves on different time scales. A possible mechanism for the vitrification phenomenon is proposed on the basis of statistical mechanics.