International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

Analysis of material condition of side frames of freight trucks before and after thermal hardening was performed by combined analysis of Acoustic Emission (AE) and strain diagrams during tests of samples cut from the frames. The kinetic of damage accumulation during loading to failure in the material after normalizing or volume-surface hardening was analyzed. Changes in ductility and toughness resource of the metal was evaluated.

In the present work, the magnesium alloy WE43 (Mg-Y-Nd-Zr) after high pressure torsion (HPT) was investigated. HPT was conducted at room temperature, 200 °C or 300 °C. As a result of HPT processing, a large number of twins with the twin size of 0.4 − 8.1 µm were formed. Furthermore, the HPT process led to the formation of a very fine grain structure with the average grain size of 30 – 100 nm. The deformation by HPT caused the formation of a displaced basal texture, which sharpens with an increase in the deformation temperature. The refinement of the microstructure brought about an improvement of the microhardness of the alloy over the as-received condition. The microhardness after HPT at the room temperature increased up to 1189 ± 33MPa compared with 774 ± 50 MPa in the initial state. A subsequent aging after HPT led to an additional strengthening to a level of 1411 ± 40 MPa. It was noted that thermal stability of strengthening caused by HPT did not depend on the deformation temperature and sustained up to 250 °C.