In-situ formation of AlN nanoparticles in NiAl-strengthened ferritic alloy with enhanced high-temperature mechanical properties via SLM fabrication

Abstract

A ferritic alloy strengthened by in-situ formed AlN and B2–Ni(Al, Mn) nanoparticles was designed using thermodynamic computational and formed via selective laser melting (SLM) fabrication. Uniformly dispersed B2–Ni (Al, Mn) and hexagonal wurtzite AlN nanoparticles in the ferritic alloy were observed by transmission electron microscopy (TEM). The incorporation of AlN nanoparticles significantly improved high-temperature performance of the alloy. The crystallographic orientation relationship (101‾0)Wurtzite//(101)α−Fe and [0001]Wurtzite//[1‾11]α−Fe between hexagonal wurtzite AlN and α-Fe was identified. Furthermore, Fe/AlN interfaces were analyzed by first-principles calculations. The results suggested that hexagonal AlN is more stable, while cubic AlN tends to precipitate in the early stages of nucleation due to its low strain energy and transforms into hexagonal AlN during prolonged heat treatment. As a result, this integrated approach provides insights into achieving superior high-temperature performance in the ferritic alloy.