The Microstructure and Mechanical Properties of Al-Mg-Fe-Ni-Zr-Sc Alloy after Isothermal Multidirectional Forging

The effects of isothermal multidirectional forging (IMF) on the grain structure, second-phase particles of solidification origin, and dispersoids in the Al-4.9Mg-0.9Ni-0.9Fe-0.2Zr-0.1Sc alloy have been investigated. The strain distribution over the sample volume during forging in a closed die has been analyzed using a finite-element simulation. A method of considering the friction effect and changes in strain rate when constructing stress-strain curves based on the IMF results has been proposed. Increasing the number of phase cycles at 350 degrees C has resulted in a two-fold decrease in the average phase particle size of solidification origin and the formation of a structure with an average grain size of 1.3 +/- 0.2 mu m, but did not change the parameters of dispersoids. IMF increased the yield strength of the alloy by 60% and the tensile strength by 20%.