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The use of DSC curves and the Kronmüller theory to study the level of structural defects of Fe-based bulk amorphous alloys

Jeż Bartłomiej, Nabiałek Marcin

Bulletin of the Polish Academy of Sciences. Technical Sciences

2023

Vol. 71, nr 2

art. no. e144613

This article presents the results of tests carried out on rapid quenched Fe-based alloys. The alloys were made using an injection-casting method. The actual structure of the alloys was also studied using an indirect method, based on H. Kronmüller's theorem. Based on analysis of the primary magnetization curves, in accordance with the aforementioned theory, it was found that Mo causes a change in internal regions associated with changes in the direction of the magnetization vector. The evolution of the thermal properties with increasing volume of Mo has been confirmed by the DSC curves. Addition of Mo, at the expense of the Nb component, results in changes to the crystallization process (i.e. the crystallization onset temperature and number of stages). The study showed that the addition of Mo at the expense of Nb reduces glass forming ability. Based on the DSC analysis, free volumes were determined for the alloys tested. These values were compared with the analysis of primary magnetization curves. It was found that the DSC curves can be used to indirectly describe the structure of amorphous alloys similar to the theory of the approach to ferromagnetic saturation. This approach is new and can be used by many researchers in this field.

Analiza porównawcza struktury wewnętrznej implantów hydrofilowych oraz hydrofobowych stosowanych w chirurgii okulistycznej metodą spektroskopii czasów życia pozytonów

Chamerski K.

Technical Issues

2015

nr 3

3--10

In presented work internal structures of intraocular lenses were analyzed in terms of defectiveness degree. Studies were conducted by means of positron annihilation lifetime spectroscopy method PALS. The aim of the work was determination of basic parameters describing annihilation centers in research materials, such as positron lifetime in bulk material, mean positron lifetime in the internal structure, positron trapping rate by trapping centers as well as free volumes dimensions. In obtained results differences in free volumes and positron traps concentrations between hydrophilic and hydrophobic materials were noted. Furthermore, comparison of materials with and without blue light chromophores revealed differences in positron trapping rate by multivacancy-like free spaces. Achieved results were referenced for mechanical properties of the studied materials.