The prototype software was modified to count stress sin2ψ method based on the geometric center of gravity of the peaks. Based on data smoothed fitted linear background, which then is subtracted from the raw data and the smoothed data, which served to match one of the specified distribution function. For now uses Gaussian distributions, Cauchy, Lorentz and Pearson VII. It is expected to use a combination of the distributions of typical peaks, such as the separated components of Kα and Kβ. Distributions were determined on the basis of the measured peak ends, and this was done in several ways. In the first stage background was subtracted and counted three ranges: standard deviation, maximum width of the peak intensity and the full range of data best suited for distribution. In the second stage, left background, and counted two ranges: the standard deviation and the maximum width of the peak intensity for the best-matched schedule. Calculated by these methods zwłascza principal stresses and principal stress angle of incidence showed a fairly significant differences.

Another month has passed...In May I focused on analysis of results which I obtained from micromechanical tests and FTIR studies. I’ve also summarized the thermal stability experiments. Calorimetric measurements and microscopic analysis of endothelial cell growth kinetics showed that polyelectrolyte multilayer films are stable in a broad range of temperatures. All results obtained so far were used to prepare a poster for the E-MRS 2012 Spring Meeting conference, for symposium focused on functional biomaterials.

During last month I was investigating morphology and mechanical properties (mainly micro-hardness) of composite powders after 40 h of high energy ball milling. For that purpose I used optical microscope, scanning electron microscope (SEM) equipped with EDAX energy dispersive X-ray (EDX) detector, X-ray powder diffractometer and micro-hardness tester.
I also attended some lectures during “Practical applications of thermal analysis methods in Materials Science” workshop, which was organized in our Institute.

Main studies carried out during May:


- TEM ad SEM investigations of ribbons microstructure in as spun state and after annealing
- Chemical composition analysis combined with elemental mapping of sample after in-situ heating and after isothermal annealing to investigate changes in elements distribution within quasicrystalline particles after thermal treatment
- determination of the sequence of crystalline phase formation based on data obtained from transmission electron microscopy and XRD analysis
- analysis of the results obtained so far,
- participation in the local composite platform meeting
- participation in seminars and lectures
- receiving the scholarship from the Doctus program

In May due to upcoming EMAS workshops, effort was done to prepare more zinc samples in order to confirm previous observations and collect proper amount of data for statistics. Unfortunately as previous EBSD observations revealed, preparation of zinc samples in a way that no distortion to the crystalline lattice and no twins are introduced is considerable problem and cannot be carried out in short time span. This is true especially for preparation of samples from non deformed zinc (initial state) which is generally softer and quite easily deformed during cutting and grinding. Introduced layer of deformation with deformation twins is then extremely hard to remove during mechanical polishing as affected layer can have thickness up to hundreds of micrometers (at least one grain layer). Partial solution to this problem is removal of deformed and twinned material during chemical etching. This method is faster and does not introduce additional deformation, however it also does not produce flat, even surface. This is due to differences of etching speed of crystals in different orientations, as well as much faster etching of grain boundaries. Because of this etching has to be followed with careful grinding on 2500 SiC grinding paper in order to remove topography and produce surface suitable for EBSD analysis.