Dislocations in nanostructured two‐phase Fe₃₀Ni₂₀Mn₂₀Al₃₀

Abstract

In a previous study, the dislocations in Fe(30)Ni(20)Mn(25)Al(25) (at. %), which consist of 50 nm wide alternating b.c.c. and B2 phases, were shown to have a/2<111> Burgers vectors after room temperature deformation. The dislocations were found to glide in pairs on both {110} and {112} slip planes and were relatively widely separated in the b.c.c. phase, where the dislocations were uncoupled, and closely spaced in the B2 phase, where the dislocations were connected by an anti-phase boundary. In this article, we analyze the dislocations in the two ~5 nm-wide B2 phases in a related two-phase alloy Fe(30)Ni(20)Mn(20)Al(30), with compositions Fe-23Ni-21Mn-24Al and Fe-39Ni-12Mn-34Al, compressed to ~3% strain at a strain rate 5 × 10(-4) s(-1) at 873 K (the lowest temperature at which substantial plastic flow was observed). It is shown that slip occursby the glide of a<100> dislocations. A review of the literature suggests that the differences in the observed slip vector between these B2 phases could be due to the differences in composition, differences in deformation temperature, or possibly both.

Dislocations in B2/L21 Fe30Ni20Mn20Al30 after High Temperature Deformation

“…In contrast, no dislocations were observed in the related two-phase B2/L2 1 alloy Fe 30 Ni 20 Mn 20 Al 30 after room temperature straining [2]. However, slip was found to occur by the glide of a<100> dislocations at 873 K, the lowest temperature at which substantial plastic flow was observed [2].…”