Abstract
The conference paper reports results of a study aimed at understanding precipitation processes of the binary Al–Mn and quaternary Al–Mn–Sc–Zr alloy. The alloys were investigated in the mould-cast state and coldrolled state.
The alloys were studied during step-by-step quasilinear annealing from 200 °C up to 600 °C with heating rate 100 K/h followed by subsequent isothermal annealing at 600 °C/4 h. The effect of the pseudohomogenization heat treatment (610 °C/18 h) on mechanical properties of the alloys during isothermal annealing at 300, 400 and 500 °C was also investigated.
Precipitation reactions were studied by electrical resistometry and (micro)hardness measurements. The microstructure development was investigated by transmission, scanning electron microscopy and electron diffraction examinations.
The hardening effect is due to fine, coherent, uniformly distributed Al3Sc and/or Al3(Sc,Zr) particles. The distinct changes in resistivity of the cold-rolled alloys at temperature above ~ 300 °C are mainly caused by precipitation of Mn-containing particles.
Precipitation of these particles has an insignificant effect on microhardness.