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Библиогр.: 51 назв.

Aluminum piston alloys of the AA4032 type are produced by direct-chill (DC) casting and
subsequent forging; therefore, it is important to understand their thermomechanical behavior.
In recent years, it was shown that additions of Cu and Er could improve mechanical properties
of these alloys at room and high temperatures. In this work, we studied the constitutive behavior
of AA4032-type alloys with and without Cu and Er additions. The experimental true stress–true
strain curves were obtained by compression tests under various temperatures [683 K to 723 K
(410 C to 450 C)] and strain rates (0.01 to 10 s1) to determine constitutive parameters
[strain-rate sensitivity, activation energy, and Zener–Hollomon (Z) parameter] for the hot
deformation behavior of AA4032-type piston alloys with and without additions of Cu and Er.
The flow stress decreased with increasing deformation temperature and decreasing strain rate.
The results also showed that increasing the Cu content increased the flow stress over the applied
range of deformation conditions due to solid-solution strengthening and the formation of
primary Si particles, which led to an increase in the activation energy during hot deformation.
Moreover, the main microstructural damage in the AA4032 alloy with 3.5 pct Cu was
predominantly due to the cracking of primary Si particles. Additions of 0.4 pct Er and 3.5 pct
Cu lower the activation energy of deformation, Q, as compared to the base alloy and the alloy
with 3.5 pct Cu. The microstructures in the deformed specimens consisted of subgrains,
recrystallized grains, and fine eutectic phases. The alloys containing Er demonstrated more
polygonized grains at a low strain rate than the alloys without Er, indicating that Er hindered
recrystallization development. The peak stress of the AA4032 alloy with 3.5 pct Cu alloy was
higher than for the base AA4032 alloy and for the AA4032 alloy with 3.5 pct Cu and 0.4 pct Er
additions, which was attributed to the prevalence of the work-hardening mechanism over the
softening mechanism.