HIGH-TEMPERATURE CHARACTERISTICS OF PLASTICITY OF MAGNESIUM ALLOYS

The development of deformable magnesium alloys and plastic forming methods has been strongly limited so far. Plastically worked magnesium alloys are very rarely used due to technological difficulties in plastic working and to high production costs. Alloys for plastic working are more and more promising, however, due to the elaboration of new ones and development of the technologies of processing them. A major drawback of magnesium and its alloys is their low deformability at ambient temperature, which is due to the type of crystallographic lattice. The favourable properties of magnesium account for the fact that it is applied not only in cast structural components but also in those subjected to plastic working. The paper presents analysis of plasticity characteristics and microstructure of magnesium alloys for hot plastic treatment with different aluminium content (3 and 8%). Susceptibility of magnesium alloy to cracking in high temperatures was tested on Gleeble3800 simulator on which zero resistance temperature and zero plasticity were determined. Tests were conducted for assessment of susceptibility of tested alloys to hot plastic deformation. A tensile test was realized in temperature from 250 to 450 degrees C. On the basis of the results, ultimate tensile strength (UTS) and reduction of area (Z) were determined for samples. A varied plasticity of tested alloys was found depending on aluminium content. Tests results will be useful in development of forging technology of chosen construction elements which serve as light substitutes of currently used materials.