Ondřej Hilšer

Mechanical properties and structure of AZ61 magnesium alloy processed by equal channel angular pressing

An equal channel angular pressing (ECAP) procedure has been developed to produce a fine-grained AZ61 magnesium alloy. The results show that the microstructure can be effectively refined with increasing equivalent strain during ECAP. For increasing ECAP process efficiency was conventional tool as a helix in the horizontal part of channel built. This fine-grained alloy has an excellent strength accompanied by reasonable good tensile ductility. The success of the development of this ECAP procedure can offer a good opportunity for the development of magnesium alloys with good mechanical properties.

The Influence of Severe Plastic Deformation Process on Structure and Properties of AZ 31 Alloy after Selected Heat Treatment

The technology of structure refinement in materials with the aim of achieving substantial mechanical properties and maintaining the required plasticity level is becoming increasingly useful in industrial practice. Magnesium alloys are very progressive materials for utilization in practice thanks to their high strength-to-weight ratios (tensile strength/density). The presented paper analyses the effect of the input heat treatment of the AZ31 alloy on the change of structure and strength properties through the process of severe plastic deformation (SPD), which finds an increasing utilization, especially in the automotive and aviation industry. For the study of the influence of the SPD process (ECAP method) on the properties of the AZ31 alloy, two types of thermal treatment of the initial state of the structure were selected. The analysis of the structure of the AZ31 alloy was performed in the initial state without heat treatment and subsequently after heat treatment. In the next part, the influence of the number of passes on the strengthening curves was evaluated. Mechanical properties of the AZ31 alloy after ECAP were evaluated by hardness measurement and completed by structure analysis.

Modification of Microstructure and Properties of Extruded Mg-Li-Al Alloys of α and α+β Phase Composition using ECAP Processing, Acta Physica Polonica A 1313, 1303 (2017), ERRATUM

Modification of Microstructure and Properties of Extruded Mg–Li–Al Alloys of α and α + β Phase Composition using ECAP Processing J. Dutkiewicza,∗, S. Rusz, W. Maziarz, W. Skuza, D. Kuc and O. Hilser Institute of Metallurgy and Materials Science, Polish Academy of Sciences, W.S. Reymonta 25, 30-059 Kraków, Poland Technical University Ostrava, Department of Mechanical Engineering, 17 Listopadu 15, Ostrava, Czech Republic Silesian Technical University, Department of Metallurgy and Materials Science, Z. Krasińskiego 8, 40-019 Katowice, Poland

Grain Refinement of AZ61 Alloy after ECAP Processing

Electron microscopy techniques were used to characterize the microstructure and deformation behavior of AZ61 alloy proceeded by ECAP. The commercial AZ61 alloy subjected to severe plastic deformation possesses a two-phase microstructure consisting of solid solution matrix and massive γ-phase Mg17Al12, or Mg17(Al,Zn)12 distributed mostly at grain boundaries. Based on selected area diffraction and electron back scattered diffraction applied to a sample after the third pass, it can be concluded that plastic deformation induced by ECAP occurs mainly by slip mode forming a high density network of dislocation inside the grains. The grains size was significantly refined to 1.4 μm after the third pass of ECAP. The refinement of grain size is probably due to polygonization process associated with formation of high angle grain boundaries due to dislocations rearrangement. (Al, Zn)12Mg17 precipitates of size scattered from 100 to 200 nm and also the primary precipitates of Al6Mn phase were observed in this alloy.