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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

Фамилия
Khalil
Имя
Asmaa
Отчество
Mostafa
Номинация
Материаловедение
Институт
Институт экотехнологий и инжиниринга (ЭкоТех)
Кафедра
Кафедра металловедения цветных металлов (МЦМ)
Академическая группа
Advanced metallic material and engineering
Научный руководитель
Prof. V.S. Zolotorevsky
Название тезиса
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
Тезис

 The influence of laser beam welding on mechanical properties will be investigated. The material used in the present work was 1545 K alloy with the chemical composition (Al-4,7%Mg-0,3%Mn-0,2%Sc-0,09%Zr-0,001%Be-<0,1%Cu-<0,1%Fe-<0,1%Zn). This alloy rolled from a 280-mm-thick industrial ingot to sheets with thicknesses of 10 mm. The 10-mm sheets were rolled to a thickness of 1 mm using only cold (at room temperature) rolling with one intermediate annealing step at 250 °С for 1 h, After getting sheet with 1mm thickness, 4x4 mm dimension was cut and prepared for welding by Electropolishing edge sides with 20V and drying 150°C 10 minutes. The laser welding conditions were voltage range from 310 to 350 V, laser defocusing is -2, duration 14 ms, and filler metals of (same alloy, Al-3%Ti-1%B) were used.The investigations of the structure, mechanical properties before and after annealing were carried out. There are two different type of the structure has found the first type is a mix of equiaxed grains zone (at the center) and columnar grains zone (the edges) with the same alloy as a filler metal the second type is small grains with 3,9±0,2 µm with Al-3%Ti-1%B filler metal​ Fig.1

                                              

The best of the mechanical properties of the samples in regards to the base metal were welded using filler metal Al-3Ti-1B. The best yield stress of welded joint and the base metal both after annealed 370 °C for 6 hours was 260,280 MPa respectively. The ratio between UTS for welded sample and base metal was (420 MPa/490 MPa) 0,85 and after rolling thickness changed from 1 to 0.8mm which deformation equal ln(L-δL/L)=0.2 and from 1.75 to 1 mm deformation was 0.6

       Finally, it can be observed that using filler metal Al-3Ti-1B for welding 1545k alloy was given good mechanical properties compared to the mechanical properties of the 1545k alloy after the same heat treatment (annealing 370°c for 6 hours).there are two welded sheets were rolled, one of them was rolled from 1 to 0.8 mm which have UTS 324.87 Mpa and elongation 1.6% and the other was rolled from 1.75 to 1 mm with the same condition of welding and heat treating which have UTS 420 MPa with elongation 1.9 %, microhardness 160 HV in the middle of welding area and 165 HV for base metal Fig.2 . There were some phases of AL3ZrSc appeared and the alloying elements diffuse through all base metal and fusion zone were equal due to the annealing process