Investigation of influence of parameters of laser welding on microstructure and mechanical properties of Al-4.7%Mg -0.32%Mn-0.21%Sc-0.09%Zr alloy

В работе исследовано влияние пиковой мощности (0,64–1,31 кВт) при напряжениях из диапазона 330–430 В при лазерной сварке со стандартным диаметром пучка и длительностью импульса 8 мс. Изучена микроструктура, сформированная сваркой. Установлено, что существует разноообразие в размерах и форме зерен в зоне шва. Показано, что с увеличением пиковой мощности ширина и глубина области шва увеличивается.In the present work the influence of peak power of laser beam welding were studied at voltage range from 330 to 430 V and peak power (0,64; 0,75; 0,87; 1,01; 1,15; 1,31) kW , and laser beam diameter is standard and duration 8 ms. The microstructure after welding was studied. It was concluded that there is a variant in grain size and shape in the welded zone and pre-welded area. The dimensions of welded zone was measured. From measuring data, it was observed, that as increasing the peak power the width and depth of welding increased.The work was performed as part of the state work "Carrying out of research work (basic research, applied research and experimental development)" state task MES of Russia in the sphere of scientific activities 2014–2016. (Task № 2014/113)

РАСЧЕТ ФАЗОВЫХ ДИАГРАММ СИСТЕМ Al–Cu–Zn–Mg и Al–Cu–Zn–Mg–Fe–Si

Using the results of thermodynamic calculations with «Thermo-Сalc» software package, the fragments of the Al–Cu–Zn–Mg and Al–Cu–Zn–Mg–Fe–Si– (Mn) phase diagrams in the range of densities, (%): 4–6 Сu, 2–4 Zn, 0,5–2,0 Mg, 1,5–2,0 Fe, 1,5–5,0 Si have been built as well as the composition of the solid solution for a number of alloys of the Al–Cu–Zn–Mg–Fe–Si–(Mn) system has been calculated at temperatures near to the solidus line. The X-ray microspectral analysis was used for experimental proof of the thermodynamic calculations, which show the satisfactory precision of the calculated and experimental data. It is found that maximally alloyed aluminum solid solution can be produced at an iron and silicon density ratio of Fe/Si = 0,5 for the alloys of the Al–Cu–Zn–Mg–Fe–Si–(Mn) system.По результатам термодинамических расчетов с использованием пакета программ «Thermo-Сalc» построены фрагменты фазовых диаграмм Al–Cu–Zn–Mg и Al–Cu–Zn–Mg–Fe–Si–(Mn) в интервале концентраций (%) 4–6 Сu, 2–4 Zn, 0,5–2,0 Mg, 1,5–2,0 Fe, 1,5–5,0 Si, а также рассчитан состав твердого раствора для ряда сплавов системы Al–Cu–Zn–Mg–Fe–Si–(Mn) при температурах вблизи солидуса. Методом микрорентгеноспектрального анализа проведена экспериментальная проверка термодинамических расчетов, которая показала удовлетворительную сходимость расчетных и экспериментальных данных. Выявлено, что при соотношении концентраций железа и кремния Fe/Si = 0,5 для сплавов системы Al–Cu–Zn–Mg–Fe–Si–(Mn) возможно получение максимально легированного алюминиевого твердого раствора

Development prospects of keratoplasty in Moscow

<p>A retrospective analysis of the statistical data for the years 2010‑2012 on mortality and the donor selection of the Bureau of Forensic Pathology of Moscow, Department of Forensic Pathology of Pirogov N. I. Russian National Research Medical University and ILab Eye Bank in order to determine the possible number of keratoplastic surgeries. The results of statistical data analysis testify to the fact that the number of available donor material is not sufficient to meet the needs for keratoplastic material and it is necessary to create eye banks, which would have provided this need. It is necessary to create eye banks, that possess a clear logistics chain of intake donor tissue, preliminary assessment of the donor tissue, laboratory diagnostics of the donor’s blood and delivery of tissue to the Bank. The<br />eye bank should not only produce preserved material for keratoplasty, but also carry out full morpho-functional assessment of material and its subsequent delivery to consumers in health facilities.</p