Thermal diffusivities and molar volumes of ternary Al20 AsxTe80Kx alloy glasses: evidence of self-organization
نویسندگان
چکیده
Thermal diffusivities (a) and molar volumes (Vm) of bulk Al20AsxTe80Kx alloy glasses in the composition range 0%x%35 are examined. The results reveal a broad maximum in alpha and a broad minimum in Vm in the 15!x!25 range. Earlier temperature modulated differential scanning calorimetric measurements on these glasses have revealed the non-reversing heat flow to show a global minimum (reversibility window) in the same composition range. Taken together these results suggest that present glasses in the 15!x!25 range are self-organized. The thermal diffusivity maximum observed near xZ20 is consistent with a minimal scattering of thermal waves in the homogeneous and stress-free glass composition residing in the center of the self-organized phase. PACS: 78.55. Qr; 65.60.Ca; 78.66 jg
منابع مشابه
Ageing, fragility and the reversibility window in bulk alloy glasses.
Non-reversing relaxation enthalpies (ΔH(nr)) at glass transitions T(g)(x) in the P(x)Ge(x)Se(1-2x) ternary display wide, sharp and deep global minima ([Formula: see text]) in the 0.09<x<0.145 range, within which T(g) s become thermally reversing. In this reversibility window, glasses are found not to age, in contrast to ageing observed for fragile glass compositions outside the window. Thermal ...
متن کاملAging, Fragility and Reversibility Window in Bulk Alloy Glasses
Non-reversing relaxation enthalpies (∆H nr) at glass transitions T g (x) in the P x Ge x Se 1-2x ternary display a wide, sharp and deep global minimum (~0) in the 0.09 < x < 0.145 range, within which T g becomes thermally reversing. In the reversibility window these glasses are found not to age, in contrast to aging observed for fragile glass compositions outside the window. Thermal reversibili...
متن کاملMicrostructure, mechanical and thermal properties of chalcogenide glasses and glass-ceramics based on Se-As-Ge system nucleated by Sn
In particular, chalcogenide glasses and glass-ceramics are new materials that exhibit good transparency in infrared region (0.8-12µm). We can overcome the main weakness of these glasses by improving the hardness through controlling crystallization. In this paper, we report results of a study on chalcogenide glasses in the ternary system of As-Se-Ge with nominal composition of Snx (Se...
متن کاملEffect of Ni on Amorphization of Ti-Cu-Ni Ternary alloys Prepared by Mechanical alloying
Amorphous alloys has been taken into consideration because of their unique properties and are nominated as the future engineering materials. In this research, the effect of Ni and milling time on amorphization process and thermal stability of Ti50Cu50-xNix(x=10, 15, 25 at%) alloy system were investigated. The evolution of amorphization during milling, thermal stability and subsequent heat treat...
متن کاملFast-track communication Meeting experimental challenges to physics of network glasses: Assessing the role of sample homogeneity
We introduce a Raman profiling method to track homogenization of GexSe100−x melts in real time, and show that 2 g melts reacted at 950 °C in high vacuum homogenize in 168 h on a scale of 10μm. Homogenization of melts is precursive to self-organization of glasses. In the present glasses, compositional variation of Raman active corner-sharingmode frequency of GeSe4 units,molar volumes, and the en...
متن کامل