In January with the help of my prominent supervisors, which I have the privilege to work alongside with, we produced ribbons via a melt spinning technique. This method is based on rapid cooling of molten materials leading to quick solidification. There were four ingots prepared with nominal composition of Ni48Mn39.5Sn12.5, Ni48Mn39.5Sn11.5Al1, Ni48Mn39.5Sn10.5Al2, Ni48Mn39.5Sn9.5Al3 denoted as NMS, NMSA, NMSAA, NMSAAA respectively. The subsequently obtained ribbons were XRD and TEM analysed (only the first NMS sample was studied this month due to time constraints). During this task I had the opportunity to familiarize myself with the method utilized for fabrication of thin foils specific for Transmission Electron Microscopy studies. TEM observation showed very interesting results. Amongst them there were the so called tweed contrasts seen in the examined sample indicative of segregation processes. Also it was noticed that the resulting average elemental chemical composition slightly shifted with respect to the staring one. This is in accordance with literature and was reported in a paper by B. Hernando et al. (Journal of Magnetism and Magnetic Materials V. 321 April 2009), which I came across. Nevertheless this interesting finding requires further studies.
The research goes on…

In Januar,

New Year has started with application the Miedema and de Boer theory for calculation the formation enthalpies of metallic alloys, for example Fe-Ti. Yielded results was compared with DFT calculation. As is well known, Miedema’s group developed a widely used thermodynamic theory for calculating the formation energies of binary transition metal alloy systems. From first principles, one could calculate the formation energy of any alloy system, however, it is usually very complicated and requires approximations and assumptions in the calculation especially for the ternary and higher component alloys.

In December, I took into consideration issues concerning methods of physico-chemical polyelectrolyte multilayer coatings characterization. I devoted time for a review of the literature on the use of radial flow test to determine the kinetics of cell adhesion on solid surfaces. I also made several attempts to analyze the value of shear stress in the system: blood - material with a modified surface. I also prepared a series of samples for preliminary analysis of FTIR (Fourier Transform Infrared Spectroscopy) and verifying the optimal stiffness of the system for settlement of cells such as smooth muscle and endothelial cells.

Main studies carried out during December:

- analysis of the results obtained so far,
- casting of new quaternary alloy,
- microstructure analysis of prepared ingot using SEM,
- preliminary tensile tests on melt-spun ribbons with molybdenum addition using INSTRON 6025,
- microstructure analysis of melt-spun ribbons with vanadium addition using TEM,
- participation in seminars and lectures

If the title is just 'report', that means that nothing really exciting happened... I have been slowly developing my tools for geometric grain boundary characterization, and collecting ideas for futher work. Hopefully, I should be able to analyze some statistical samples soon. What is more, there appeared the idea of comparing two methods for detecting GB character, as far as I know they have not been confronted yet.