Hits:

Indexed by:期刊论文

Date of Publication:2016-08-15

Journal:JOURNAL OF ALLOYS AND COMPOUNDS

Included Journals:SCIE、EI、Scopus

Volume:676

Page Number:565-574

ISSN No.:0925-8388

Key Words:Fe-based alloys; Ideal tensile strength; ab initio; Structural energy difference

Abstract:Using ab initio alloy theory formulated within the exact muffin-tin orbitals theory in combination with the coherent potential approximation, we investigate the ideal tensile strength (ITS) in the [001] direction of bcc ferro-/ferrimagnetic (FFM) and paramagnetic (PM) Fe1-xMx (M = Al, V, Cr, Mn, Co, or Ni) random alloys. The ITS of ferromagnetic (FM) Fe is calculated to be 12.6 GPa, in agreement with available data, while the PM phase turns out to posses a significantly lower value of 0.7 GPa. Alloyed to the FM matrix, we predict that V, Cr, and Co increase the ITS of Fe, while Al and Ni decrease it. Manganese yields a weak non-monotonic alloying behavior. In comparison to FM Fe, the alloying effect of Al and Co to PM Fe is reversed and the relative magnitude of the ITS can be altered more strongly for any of the solutes. All considered binaries are intrinsically brittle and fail by cleavage of the (001) planes under uniaxial tensile loading in both magnetic phases. We show that the previously established ITS model based on structural energy differences proves successful in the PM Fe-alloys but is of limited use in the case of the FFM Fe-based alloys. The different performance is attributed to the specific interplay between magnetism and volume change in response to uniaxial tension. We establish a strong correlation between the compositional effect on the ITS and the one on the shear elastic constant C' for the PM Fe-alloys and briefly discuss the relation between hardenability and the ITS. (C) 2016 Elsevier B.V. All rights reserved.