Evolution of eutectic spacing during unidirectional solidification of Al-Ni alloys

Abstract

Hypoeutectic Al-Ni alloys show a ductile phase α distributed with a β phase Al 3 Ni fragile where β serves as reinforcement of the structure of the material. The eutectic composition alloys obey the relationship: λ 2 .v = C, where λ is the eutectic spacing, v is a tip growth rate and C is a constant. The aim of this study is to establish correlations between λ and v for hypoeutectic Al-1%, 3% and 5% Ni alloys. Unsteady-state upward directional solidification experiments were performed, as well as metallography, dissolution of the aluminum matrix and scanning electron microscopy (SEM). The interphase spacing of the three Al-Ni alloys decreased with increasing tip growth rate, with a predominance of a rod-like morphology on intermetallic. It was observed that parameters such as tip growth rate, cooling rate and temperature gradient decreases as the solidification front advances. It was further observed that a single experimental law λ = 1.2 v-0, 5 illustrates the evolution of the interphase spacing for any examined alloy.

Effect of nickel on microstructure and wear behaviour of pure aluminium against steel and alumina counterfaces

“…The Al-Ni eutectic alloys are suitable for high temperature applications for the use in harsh environments. 21,22 Although there are a lot of studies of Al-Ni intermetallics, information about more practical properties such as hardness, wear behaviour and coefficient of friction is still lacking in the literature for Al-Ni eutectic systems. These properties have critical importance in the applications of these materials.…”