Barothermal analysis of phase transformations of an Al-15 at % Ni alloy and its structure and magnetic properties

Abstract

Phase transformations of the 15Ni-85Al alloy have been studied by differential barothermal analysis at temperatures of up to 900°C and pressures of up to ≅ 100 MPa. We have determined the pressure coefficients of the liquidus and solidus temperatures and the temperatures of solid-state dissolution and precipitation of the intermetallic phase Al3Ni in the Al matrix. Melting and crystallization in compressed argon have been shown to increase the micropore concentration in the material by about one order of magnitude relative to the as-prepared alloy. Crystallization of the alloy at 100 MPa has a significant effect on its microstructure and the particle size and morphology of the intermetallic phase in the aluminum matrix and increases the unit-cell volumes of the Al and Al3Ni. We have compared the magnetic properties of the alloy before and after barothermal analysis.