Tensile properties of hypoeutectic Al-Ni alloys: Experiments and FE simulations

Abstract

Binary Al-Ni alloys have been proven to be a promising cast aluminum alloy for high temperature services. The microstructure of the hypoeutectic Al-Ni alloys basically consists of the primary α-Al and the binary Al-Al3Ni eutectic. The volume fraction of eutectic plays an important role on the mechanical properties of the alloy. In this work, hypoeutectic Al-Ni alloys with different nickel contents were investigated through macrostructure and microstructure analyses, hardness measurements, and tensile tests. Subsequently, finite element (FE) based modelling using representative volume element (RVE) method have been developed to predict overall stress-strain characteristics of the examined hypoeutectic Al-Ni alloys. Hereby, two dimensional RVE models were generated from micrographs of the alloy at the microstructure level with varying phase fractions. The macrostructure results revealed that observed grain morphologies changed with the additions of different nickel contents. The hardness, yield strength, and ultimate tensile strength were increased with increasing amount of the eutectic phases. The calculated stress-strain responses of the hypoeutectic Al-Ni alloys were well verified with the experimental tensile curves. The micromechanics model could be then used to describe local stress and strain evolutions of the individual phases in the microstructure of studied Al-Ni alloys.