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Predicting mechanical properties of carbide-metal interfaces from first principles

Abstract : The cavity initiation observed in ductile, brittle and intergranular creepdamages is often explained by a fracture of interface between carbideand metallic lattices. Understanding the mechanisms of fracture allowsthe prediction of the cavity density as a function of applied strain,which law strongly affects the damage evolution. This study focuseson interfaces between a metallic matrix (Fe, Ni) and a representativecarbide M23C6 . Surface, interface and fracture energies are calcu-lated via DFT based on chemical potential analysis. Then, interfa-cial fractures stresses are estimated by the UBER (Universal BindingEnergy Relation) model and compared with good correlation to theresults of fully-DFT simulations of tensile test carried out using var-ious methodologies. We investigate the dependence of the interfacialmechanical behavior on chemical compositions, crystallographic struc-tures and magnetic orderings. The predicted fracture stresses of coher-ent interfaces range between 14 and 20 GPa. Then, the effects of someincoherent interfaces are investigated. The resulting critical stress isabout two times smaller, which is consistent with experimental obser-vations showing that interfacial fracture rather occurs at incoherentinterfaces. Finally, segregations effects are investigated.
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https://hal-cea.archives-ouvertes.fr/cea-02339305
Contributor : Bibliothèque Cadarache <>
Submitted on : Wednesday, October 30, 2019 - 1:34:57 PM
Last modification on : Tuesday, April 28, 2020 - 11:28:13 AM

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  • HAL Id : cea-02339305, version 1

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E. Barbe, C.-C. Fu, M. Sauzay. Predicting mechanical properties of carbide-metal interfaces from first principles. DPG and EPS Spring Meeting 2018, Symposium Fundamentals of Fracture, Mar 2018, Berlin, Germany. ⟨cea-02339305⟩

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