Structure/Property Relationships in Two-Phase f.c.c./B2 FeNiMnAl Alloys

In recent DOE-funded work (Baker et al., Materials Characterization, 62 (2011) 952-958) we discovered a series of two-phase FeNiMnAl alloys, e.g., Fe25Ni25Mn30Al20, Fe30Ni20Mn30Al20, Fe28Ni18Mn33Al21, that consist of 65-85 nm wide, blocky, alternating f.c.c. and B2 phases with a [100]B2//[110]f.c.c:(002)B2//(002)f.c.c. orientation relationship and 50-100 nm wide grain boundary f.c.c. phases, which exhibit room temperature yield strengths up to 1200 MPa. The aim of this project is to develop an understanding of the microstructural stability and deformation mechanisms that control the strength of these potentially-useful f.c.c./B2 FeNiMnAl alloys over a range of temperatures and strain rates. The effects of chromium additions, which can increase the ductility and ameliorate the environmental embrittlement of these alloys is also being examined.

Funded by the Department of Energy, Basic Energy Sciences