Tensile Properties at Elevated Temperature of Al-Cu Alloy Inoculated by ZrCuAlNiLa Amorphous Alloy

（Zr₅₅Cu₃₀Al₁₀Ni₅）_97.2La_2.8 amorphous alloy was prepared by suction casting method, and was added as an inoculant to the Al-Cu alloy melt followed by casting. The alloy was subjected to heat treatment under solution at 811 K for 10 h and aging at 438 K for 10 h. The microstructure of the inoculated Al-Cu alloy and its elevated temperature tensile properties at test temperatures of 433–493 K and strain rates of 10⁻³–10⁻¹ s⁻¹ were studied. The results show that inoculation treatment of ZrCuAlNiLa amorphous alloy could significantly refine the grains of Al-Cu alloy, reducing the average grain size of α-Al dendrites from 185 mm before treatment to 38 mm. With the increase of strain rate or the decrease of test temperature, the tensile strength of the inoculated alloy increased. The tensile strength and percentage elongation after fracture of the inoculated alloy under the same condition were significantly higher than those of the uninoculated alloy. The tensile strength of the inoculated alloy was the highest at a temperatur of 433 K and a strain rate of 10⁻¹ s⁻¹, which was 418 MPa, and the percentage elongation after fracture was 14.7%; both of them increased by 36% and 25%, respectively, compared with those of the uninoculated alloy. The main mechanism for improving the elevated temperature tensile performance of Al-Cu alloy inoculated with ZrCuAlNiLa amorphous alloy was fine-grained strengthening and second-phase strengthening. At elevated temperatures, the tensile fracture mechanism of the inoculated alloy exhibited a mixed fracture mode dominated by transgranular fracture and supplemented by intergranular fracture. Compared with that of the uninoculated alloy, the dimples on the tensile fracture surface of the inoculated alloy were smaller and more evenly distributed.