Reactive Casting of Ni–Al–Fe Ternary Intermetallic Alloys

Abstract

NiAl-base intermetallic alloys containing iron up to 25 at% are produced by reactive casting, which involves an exothermic reaction between elemental liquids and enables one to cast high-melting-point intermetallic alloys without the need of external heating. In this study, aluminum liquid at 1023 K and a moltennickeliron alloy at 1773 K are mixed to produce a molten Ni–Al–Fe ternary intermetallic alloy with a temperature of over 2300 K, which is approximately 400 K higher than the melting point of the alloy produced. The concentrations of the constituent elements are approximately homogeneous in the ingot of 30 mm in diameter and 130 mm in height. The grain size of the ingot decreases, as the iron content increases. The increase in iron content improves the hardness, bending strength and wear resistance of the alloy. Young's modulus of the alloy decreases with the increase in temperature and iron content.