Effect of extrusion on the microstructure, deformation and thermal behavior during tension of Mg-2.9Y-1.3Nd alloy

A comprehensive study of the microstructure, mechanical properties and patterns of accumulation and dissipation of energy of the magnesium alloy Mg-2.9Y-1.3Nd in the recrystallized state and after severe plastic deformation (SPD) by extrusion was carried out. It has been shown that SPD by extrusion of a magnesium alloy leads to the formation of a bimodal structure consisting of grains with an average size of 15 µm, and ultrafine grains with sizes less than 1 µm and a volume fraction of up to 50%, as well as fine particles of the second phases Mg_{24Y5. It has been established that grain refinement during the extrusion process is accompanied by an increase in yield strength, tensile strength by 1.5 times and ductility by 1.8 times, which is due to substructural hardening, redistribution of phase composition and texture formation. Using infrared thermography, it was revealed that before the destruction of Mg-2.9Y-1.3Nd in the recrystallized state, a sharp temperature jump of 10°C occurs, and the strain hardening coefficient becomes negative and amounts to (-6) GPa. SPD leads to the redistribution of thermal energy throughout the sample during deformation, does not cause a sharp increase in temperature and reduces the strain hardening coefficient by 2.5 times. The results obtained will make it possible to predict the deformation-temperature behavior of materials and may be in demand in a number of industries and in medical applications of new materials.}

Images of the microstructure of the extruded Mg-2.9Nd-1.3Y alloy and the dependence of energy dissipation and accumulation during plastic deformation:

a - optical image, b-d - bright-field TEM images with microdiffractions, d - recrystallized state, f - extruded state; 1 - work of plastic deformation, 2 - specific amount of heat released during deformation, 3 - absorbed energy during plastic deformation

The work was carried out within the framework of the state assignment of the Institute of Physical Problems and Problems of the Siberian Branch of the Russian Academy of Sciences, number FWRW-2021-0004. The research results were published in the highly rated MDPI journal “Metals”, (IF: 2,695; Q1). Legostaeva, E.; Eroshenko, A.; Vavilov, V.; Skripnyak, V.A.; Luginin, N.; Chulkov, A.; Kozulin, A.; Skripnyak, V.V.; Schmidt, J.; Tolmachev, A.; et al. Influence of Severe Plastic Deformation by Extrusion on Microstructure, Deformation and Thermal Behavior under Tension of Magnesium Alloy Mg-2.9Y-1.3Nd. Metals 2023, 13, 988.
https://doi.org/10.3390/met13050988.< /p>