Ab initio study of energetics and structures of heterophase interfaces: From coherent to semicoherent interfaces

Abstract

Density functional theory calculations have been performed to study the structures and energetics of coherent and semicoherent TiC/Fe interfaces. A systematic method for determining the interfacial energy for the semicoherent interface with misfit dislocation network has been developed. The obtained interfacial energies are used to calculate the aspect ratios for the disc-like precipitates and a quantitative agreement with the experimental results is reached. Based on the obtained interfacial energies and atomic structure details, we propose models for describing the evolution of the interfacial energy with respect to the size of TiC precipitate for heterogeneous nucleation on an edge dislocation, shedding light on the thermodynamics of precipitate nucleation and growth. The present method can be easily applied to any heterophase interfaces between metals and oxides/carbides/nitrides.

Improved Strength–Ductility Synergy of a CoCrNi Medium‐Entropy Alloy by Ex Situ TiN Nanoparticles

“…The majority of raw powder exhibited a spherical morphology and TiN nanoparticles were homogeneously distributed on the surface of CoCrNi powder. In comparison with conventional methods, including dry milling and wet milling in alcohol, [ 33–35 ] the key advantage of the present method is that the CoCrNi powder showed no change in morphologies after coating.…”

“…Furthermore, the corresponding strengthening mechanisms for synthesized CoCrNi/TiN composite were discussed. In comparison with conventional methods, including dry milling and wet milling in alcohol, [33][34][35] the key advantage of the present method is that the CoCrNi powder showed no change in morphologies after coating.…”

Anisotropy of the Pressure Effect in the Ti3O5 Phase Transition Process Resolved by Direction-Dependent Interface Propagation

“…The calculation of interface energies from first principles is possible and provides insight at atomistic resolution of processes at interfaces propagating through the bulk. , In theoretical models, it has to be taken into account that the space groups of the phases may differ and that their interface might be heterogeneous (for example, a (100)/(110) interface). Ref details an approach tailored to interfaces consisting of two phases of a material, which crystallize in different space groups.…”

Ab Initio Study of Energetics, Charge Transfer, and Atomic Structures of FCC Fe/NbC Interfaces with and Without N Doping: From Coherent to Semi-coherent Interfaces

“…Heterophase interfaces between metals and carbides (MCs), nitrides, and oxides are abundant in materials and can have a decisive role in the mechanical, chemical, and functional properties. 1,2,3,4 For example, in both austenitic and ferritic steels, precipitates of transition metal carbides/nitrides are widely used to adjust the mechanical and other properties. The presence of homogeneously distributed nano-sized precipitates can significantly increase the yield stress in low-carbon steels.…”

“…One of the dominant factors for controlling the growth of precipitates in steel is the interface energy between the precipitate and the iron matrix. 1,2 Nitrogen, as an alloying element, has been commonly added to stainless steel as a strong austenite stabilizer, and to improve its creep strength (toughness) and corrosion resistance. 9,10 It is believed that N can enhance toughness and corrosion resistance of stainless steel by precipitating in the form of niobium (carbo)nitrides or remaining in solid solution.…”