Decomposition of the solid solution and the formation of a high-coercivity state in Fe2NiAl alloy upon cooling at the critical rate

Abstract

Transmission electron microscopy and magnetic measurements are used to study the formation of the microstructure and magnetic properties of Fe₂NiAl (alni) alloy upon cooling at the critical rate (V ∼ 2°/min) from the region of single-phase solid solution (1240°C). Cooling is interrupted by water quenching caused by temperatures Т_quench. The periodical modulated structure formed during sample cooling at the critical rate guarantees the strongest possible coercive force (Н_с = 670 Oe). The decomposition of the solid solution below 900°C includes a stage of primary modulated structural failure upon continuous cooling to temperature Т_quench ∼ 850°C, which corresponds to the weakest coercive force on the Н_с(Т_quench) curve. The periodical modulated structure is recovered when the temperature falls further; this is accompanied by an increase in the coercive force (up to Н_с = 670 Oe) after cooling to 20°C.