**2. Experimental Methods**

Experimental aluminum alloy in the form of a long-length rod 12 mm in diameter and ≈20 m in length was manufactured using electromagnetic casting (EMC) technique (equipment of the Research and Production Centre of Magnetic Hydrodynamics (Krasnoyarsk, Russia) [27]). The alloy was prepared from commercial aluminum (99.5 wt.%). Calcium, zirconium, iron and silicon were introduced into the aluminum melt at 880–900 ◦C in the form of master alloys. The casting was carried out at a temperature of ≈830 ◦C which was higher than the alloy liquidus (810 ◦C). The fragment of long rod billet (Figure 1a) was used for experimental study. According to spectral analysis made using Oxford Instruments, the actual chemical composition of the experimental alloy (hereinafter referred to as ACZ) was close to the target one (Table 1). For a more detailed analysis of the quaternary Al-Ca-Fe-Si

system, additional studies of the microstructure of the ACZ alloy obtained during slow solidification (melt cooling rate is ~0.01 K/min) were carried out. From this, we can expect the formation of the phase composition close to the equilibrium one.

**Figure 1.** As-cast wire rod (12 mm) and cold rolled strip (**a**), and (**b**) cold drawn wire of ACZ alloy.


**Table 1.** Chemical compositions of experimental alloys.

1 Zr-free alloys (0–1 wt.% Ca) were prepared in a resistance furnace (GRAFICARBO) in a form of flat ingots (10 mm × 40 mm × 180 mm in size) and considered in section "Discussion".

> The as-cast EMC rod was processed using drawing (the reduction ratio was 94%) to obtain the wire (3 mm diameter, see in Figure 1b). The obtained wire was subjected to annealing at 350–450 ◦C together with the 2 mm strip (Figure 1a) made additionally from the as-cast EMC rod by cold rolling (using a Chinetti LM160 laboratory-scale rolling mill machine). This strip was prepped for the analysis of the influence of deformation on the decomposition of (Al) during annealing. The stepwise annealing modes (Table 2) used for all experimental samples (EMC rod, wire and strip) were previously substantiated [22]. The Vickers hardness and electrical conductivity (EC) of the samples were measured at each annealing step. The measurement was carried out at room temperature.

> Besides, the ternary and 4 quaternary alloys containing 0.5% Fe, 0.25% Si and up to 1% Ca were prepared to estimate the effect of calcium on the electrical conductivity. These alloys were poured at 750 ◦C into a flat graphite mold (of 10 mm × 40 mm × 180 mm in size). The cold rolled sheet products of 2 mm thickness were prepared from as-cast ingots.

> The microstructure was studied using scanning electron microscopy (SEM, TESCAN VEGA 3, Tescan Orsay Holding, Brno, Czech Republic), electron microprobe analysis (EMPA, OXFORD Aztec, Oxford Instruments, Oxford shire, UK), and transmission electron microscopy (TEM, JEM 2100, JEOL, Tokyo, Japan). Mechanical polishing was used together with electrolytic polishing, which was carried out at a voltage of 15 V at a temperature of −25 ◦C in an electrolyte containing 20% nitric acid and 80% methanol. The thin foils for

TEM were prepared by ion thinning with a PIPS (Precision Ion Polishing System, Gatan, Pleasanton, CA, USA) machine and studied at 160 kV.

Tensile tests for as-processed wire specimens were conducted by using a universal testing machine, model Zwick Z250 (Zwick Roell AG, Ulm, Germany). The Vickers hardness (HV) was measured using a MetkonDuroline MH-6 (METKON Instruments Inc., Bursa, Turkey) universal tester. A load of 1 kg and a holding time of 10 s were used to determine the Vickers hardness. The hardness was measured at least five times at each point.

The specific electrical conductivity (EC) of the EMC rod and the cold rolled strip was determined using the eddy current method with a VE-26NP eddy structures instrument (CJSC Research institute of introscopy SPEKTR, Moscow, Russia). The electrical resistivity of the cold drawn wire was measured for straightened samples of at least 1 m in length in the rectified part (in accordance with IEC 60468:1974 standard [28]).

**Table 2.** Annealing regimes for electromagnetic casting (EMC) rod, strip and wire.

