Characterization of deformation substructure evolution in metastable Fe49Mn30Co10Cr10B1 interstitial high entropy alloy

Interstitial alloying has been utilized to overcome the strength-ductility trade-off in high entropy alloys (HEAs). In this work, boron-doping in a typical metastable FeMnCoCr HEA is chosen to investigate deformation substructure evolution by using electron backscatter diffraction and high-angle ann...

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Veröffentlicht in:Intermetallics 2022-05, Vol.144, p.107508, Article 107508
Hauptverfasser: Tu, Jian, Xu, Kang, Liu, Yi, Luo, Jin-ru, Zhou, Zhi-ming, Ding, Li-peng
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Sprache:eng
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Zusammenfassung:Interstitial alloying has been utilized to overcome the strength-ductility trade-off in high entropy alloys (HEAs). In this work, boron-doping in a typical metastable FeMnCoCr HEA is chosen to investigate deformation substructure evolution by using electron backscatter diffraction and high-angle annular dark field scanning transmission electron microscopy, to understand how interstitial atoms tune the deformation modes. Boron-doping facilitates the formation of Cr2B particles, which can effectively decrease the grain size and retard the thermal-induced ε phase. Under the initial deformation (10% rolling reduction), the coexistence of dislocations slip in γ phase and of {10 1‾ 2} twins in ε phase is the dominant deformation modes. With the increasing strain (20% rolling reduction), the interaction of ε lamellas is significantly strengthened, which is favor of the formation of intersecting ε products. The occurring of intrinsic stacking faults in γ phase act as the nucleation sites for ε phase. Moreover, two types of dislocations (1/2 and ) are revealed in ε phase. At the ultimate deformation stage (40% rolling reduction), due to the saturation of γ → ε transformation, the coexistence of dislocations slip and twins ({10 1‾ 1} and {101‾ 3}) in ε phase can further accommodate strain, and the saturated ε phase is dominated by one persisting ε variant. Accordingly, the differences in deformation substructures of metastable FeMnCoCr HEA with or without B-doping are intrinsically arising from boron interstitial alloying effect. [Display omitted] •Boron-doping facilitates the formation of Cr2B particles.•Under the low strain, dislocations slip in γ phase and{10 1‾ 2} twins in ε phase are the dominant deformation modes.•Under the medium strain, interaction of ε lamellas is strengthened.•Under the heavy strain, {10 1‾ 1} and {101‾ 3} twins in ε phase can further accommodate strain.•1/2 (b = 1/6) and (b = ) dislocations are confirmed in ε phase.
ISSN:0966-9795
1879-0216
DOI:10.1016/j.intermet.2022.107508