Structure and phase composition of iron-nickel cast alloys with an overequilibrium nitrogen content

Microingots (2 g in mass and 3 mm in diameter) of iron-based alloys with various contents of nickel (4.5–34.0 %) and nitrogen (0.020–0.268%) were produced by melting with induction heating in the gaseous nitrogen medium under pressure. The structure, phase composition, and microhardness of the alloys are studied. The nitrogen alloying of the Fe-Ni alloys is shown to bring about an increase in the austenite content and microhardness of the alloys. The nonequilibrium phase diagram of the Fe-Ni-N cast alloys was constructed.