Baptiste Bienvenu

Max Planck Institute for Sustainable Materials | MPIE

It is generally assumed that the entropy of activation associated with dislocation glide, a process controlling body-centered cubic metals strength, is either constant or related to the enthalpy and stress through the empirical Meyer-Neldel (MN) law. We present an atomistic investigation revealing that while both cases can be encountered depending...

Synthesizing distinct phases and controlling the crystalline defects in them are key concepts in materials and process design. These approaches are usually described by decoupled theories, with the former resting on equilibrium thermodynamics and the latter on nonequilibrium kinetics. By combining them into a holistic form of defect phase diagrams,...

The combined structural and electronic complexity of iron oxides poses many challenges to atomistic modeling. To leverage limitations in terms of the accessible length and time scales, one requires a physically justified interatomic potential which is accurate to correctly account for the complexity of iron-oxygen systems. Such a potential is not y...

The effect of finite-temperature magnetic excitations on the plasticity of body-centered cubic chromium is studied. In chromium, the magnetic order is disrupted by the 12〈111〉 Burgers vectors of dislocations, creating magnetic frustrations partially resolved through the generation of magnetic faults. These faults may bear consequences on plasticity...

Crystal strength and plastic flow are controlled by the motion and interaction of dislocations, the line defects carrying atomic shear increments. Whereas, in most crystals, deformation develops in the crystallographic planes in which the glide force acting on dislocations is maximum, plasticity in body-centred cubic metals is more complex. Slip sy...

The object of this thesis is to study plasticity of chromium, considered as a coating layer of zirconium fuel claddings, and in these conditions needs to be able to accommodate the deformation which is imposed to it without cracking. Chromium is one of the seven pure body-centered cubic transition metals, however the only one with a magnetic struct...

Plasticity of body-centered cubic (bcc) metals is atypical at low temperatures, caused by the important lattice friction of 1/2〈111〉 screw dislocations. In this paper, we present a yield criterion that can be used to predict yield stress and active slip systems in all bcc transition metals for any applied stress. The criterion is fully parametrized...

Slip activity in body-centered cubic chromium is modeled by means of ab initio calculation of screw dislocations core properties and Peierls potential. As dislocations having 1/2〈111〉 Burgers vector and also 〈100〉, both gliding in {110} crystallographic planes have been reported experimentally, both screw dislocations are modeled. A generalized yie...

We show here how density functional theory calculations can be used to predict the temperature- and orientation-dependence of the yield stress of body-centered cubic (BCC) metals in the thermally-activated regime where plasticity is governed by the glide of screw dislocations with a 1/2⟨111⟩ Burgers vector. Our numerical model incorporates non-Schm...

The influence of magnetism on the properties of screw dislocations in body-centered cubic chromium is investigated by means of ab initio calculations. Screw dislocations having Burgers vectors 1/2 111 and 100 are considered, following experimental observations showing activity for both slip systems. At low temperature, chromium has a magnetic order...

We show here how density functional theory calculations can be used to predict the temperatureand orientation-dependence of the yield stress of body-centered cubic (BCC) metals in the thermallyactivated regime where plasticity is governed by the glide of screw dislocations with a 1/2 <111> Burgers vector. Our numerical model incorporates non-Schmid...

The influence of magnetism on the properties of screw dislocations in body-centered cubic chromium is investigated by means of ab initio calculations. Screw dislocations having Burgers vectors 1/2<111> and <100> are considered, following experimental observations showing activity for both slip systems. At low temperature, chromium has a magnetic or...

We study the mechanical and electronic properties of heterobilayers composed of black phosphorus (BP) on hexagonal boron nitride (hBN) and of blue phosphorus (Pblue) on hBN by means of ab initio density functional theory. Emphasis is put on how the stress applied on the constituent layers impact their structural and electronic properties. For this...

We study the mechanical and electronic properties of heterobilayers composed of black phosphorus (BP) on hexagonal boron nitride (hBN) and of blue phosphorus (\Pblue) on hBN by means of ab-intio density functional theory. Emphasis is put on how the stress applied on the constituent layers impact their structural and electronic properties. For this...