Details

Autor(en) / Beteiligte

• Liu, S.F.
• Wu, Y.
• Wang, H.T.
• Lin, W.T.
• Shang, Y.Y.
• Liu, J.B.
• An, K.
• Liu, X.J.
• Wang, H.
• Lu, Z.P.

Titel

Transformation-reinforced high-entropy alloys with superior mechanical properties via tailoring stacking fault energy

Ist Teil von

• Journal of alloys and compounds, 2019-07, Vol.792, p.444-455

Ort / Verlag

Lausanne: Elsevier B.V

Erscheinungsjahr

2019

Link zum Volltext

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Face-centered cubic (fcc) HEAs, particularly the typical FeCoNiCrMn HEA, are promising for cryogenic applications but generally exhibit relatively low strength at ambient temperature, which limits their widespread uses. In this work, we present a systematic study of enhancing simultaneously the strength and ductility of FeCoNiCrMn HEAs via tailoring the phase stability and stacking fault energy (SFE). It was found that in Fe20CoxNi40-xCr20Mn20 (x = 20–30 at.%) HEAs, with the increase of Co, the SFE was gradually decreased and another hcp (hexagonal close-packed) phase was eventually formed in the alloy containing 28 at.% Co. As a result, the deformation mode changes from dislocation glide to mechanical twinning, then to γfcc → εhcp martensitic transformation. Our analysis indicates that the small critical shear stress for twinning resulted from the reduced SFE provides a steady strain hardening rate in a wide strain regime and postpones the plastic instability, eventually leading to the concurrent enhancement in the tensile strength and ductility. Our results not only shed lights on understanding of the effects of SFE on the mechanical properties, but also have important implications on the development of HEAs with a unique combination of high strength and large ductility. •Increase of the Co content decreases the SFE and phase stability of FeCoNiCrMn alloy.•TRIP effects were achieved with the increase of Co content.•Increase of Co enhances the strength and ductility simultaneously.•Effects of the SFE on deformation mechanism were explored.