Structure and mechanical properties of Al–Ca–Mn–Fe– Zr–Sc eutectic aluminum alloy after equal channel angular pressing

Abstract

Multicomponent eutectic alloys developed in recent years based on the Al–Ca system have high practical application prospects due to their low density, high corrosion resistance, good processability when casting, and high formability in the as-annealed state. Alloy hardening is achieved by doping with Mn, Fe, Zr, Sc and other elements. Obtaining an ultrafine-grained state in aluminum alloys by the methods of severe plastic deformations, e.g. equal channel angular pressing (ECAP), significantly increases the complex of their mechanical properties. In this regard, the purpose this paper was aimed to study the effect of warm ECAP on the structure, mechanical properties and thermal stability of the eutectic aluminum alloy, wt.%: Al–3.5Ca–0.9Mn–0.5Fe–0.1Zr–0.1Sc. The ECAP process was carried out on as-cast alloy specimens with a diameter of 20 mm (temperature 400 °C, route BC, channel intersection angle 110°, number of passes N = 6). It is shown that as a result of ECAP, a developed substructure with high-density dislocations and released nanosized Al6(Mn, Fe), and Al3Sc particles is formed in the alloy, as well as primary coarse Al6(Mn, Fe) particles and eutectic Al4Ca particles are reduced in size. Such a change in the structure during ECAP leads to the significant hardening of the alloy: its strength properties increased by 1.5–2.0 times, and relative elongation decreased by 1.3 times in the longitudinal section sample and slightly changed in the «transverse» section sample as compared to the initial condition.