Morphological features of crystal growth in the Al87Ni8Y5 alloy on rapid cooling of the melt under high pressure

Abstract The authors have performed a comparative study of the structures of the hypereutectic Al87Ni8Y5 alloy (hereinafter indicated at.%) obtained by rapid cooling from the liquid phase during crystallization under pressure (from 1.8 to 2.2 GPa and 7 GPa), subject to temperature changes (from 1200 to 1800 °C) of the melt, through durametry, X-ray structural analysis and optical and electron microscopy. It is shown that under all the considered conditions of crystallization and the cooling rate of the melt of 103 K/sec, there are formed crystalline phases in the alloy. Dense homogeneous structures of the alloy with dispersed primary ternary aluminides Ni and Y of variable composition (with different contents of Ni and Y) or anomalously oversaturated α-Al-solid solution and modified eutectic, which have high hardness, are obtained.