Microstructural, mechanical, and electrical characterization of directionally solidified Al–Cu–Mg eutectic alloy

The composition of an Al–Cu–Mg ternary eutectic alloy was chosen to be Al–30 wt% Cu–6 wt % Mg to have the Al2Cu and Al2CuMg solid phases within an aluminum matrix (α-Al) after its solidification from the melt. The alloy Al–30 wt % Cu–6 wt % Mg was directionally solidified at a constant temperature gradient (G = 8.55 K/mm) with different growth rates V, from 9.43 to 173.3 μm/s, by using a Bridgman-type furnace. The lamellar eutectic spacings (λE) were measured from transverse sections of the samples. The functional dependencies of lamellar spacings λE ( λ _Al₂CuMg λ A l 2 C u M g and λ _Al₂Cu λ A l 2 C u in μm), microhardness H V (in kg/mm2), tensile strength σT (in MPa), and electrical resistivity ρ (in Ω m) on the growth rate V (in μm/s) were obtained as λ _Al₂CuMg = 3.05V- 0.31 λ A l 2 C u M g = 3.05 V − 0.31 , λ _Al₂Cu = 6.35V- 0.35 λ A l 2 C u = 6.35 V − 0.35 , HV = 308.3( V )- 0.33 H V = 308.3 ( V ) − 0.33 ; σT= 408.6(V)0.14, and ρ = 28.82 × 10–8(V)0.11, respectively for the Al–Cu–Mg eutectic alloy. The bulk growth rates were determined as λ _Al₂CuMg²V = 93.2 λ A l 2 C u M g 2 V = 93.2 and λ _Al₂Cu²V = 195.76 λ A l 2 C u 2 V = 195.76 by using the measured values of λ _Al₂CuMg λ A l 2 C u M g , λ _Al₂Cu λ A l 2 C u and V. A comparison of present results was also made with the previous similar experimental results.