Microstructures and mechanical properties of Ni₃Al alloyed with iron additions

The alloying behavior of iron in B-doped Ni₃Al was studied using optical and transmission electron microscopy for microstructural analysis and tensile testing for mechanical property evaluation. The aluminide dissolves less than 15 at. pct iron. At iron levels of 15 pct, depending on the aluminum level, formation of both transformed B2 phase (β^′) and disordered fee phase (γ) is observed. The phase relationships in the aluminide containing 10 pct iron were studied in detail by quenching from temperatures below 1370 °C. Tensile properties of nickel-iron aluminides were determined as functions of iron content and test temperature. The tensile results are discussed in terms of solid-solution hardening, atomic size misfit, and precipitation of γ, β^′, and carbides. © 1987 The Metallurgical of Society of AIME.