We are looking for a PhD student to investigate the effects of alloying on the plastic deformation of titanium using ab initio calculations (see summary below + attachment for a detailed description of the position). The research will be performed in the Jean Lamour institute, one of the largest materials science institute in Europe located in Nancy, France.

Application instructions Email a resume, statement of motivation, grades for the past 2 academic years and contact of 2 references to [email protected]

Application deadline Apr. 1st 2017

Goal The proposed Ph. D. aims at investigating the effect of alloying Ti with V and Al on dislocation mobility using ab initio calculations. These elements are the two main additives for titanium alloys used in the aeronautics industry. Such an approach has already enabled understand elementary mechanisms at stake in Ti-O (interstitial) plasticity but was never used to study the effect of substitution alloying.

Scientific Context Mass reduction of structural materials is one of the main challenges faced by the aeronautic industry in order to reduce greenhouse gas emissions. Titanium alloys are widely used in this context since they are light and have a large tensile stress. The α phase of Ti alloys (with an hexagonal close-packed structure) is however known to be responsible for cold dwell fatigue, an unsolved engineering problem responsible for early ageing of Ti alloys. This phenomenon is known to originate from the plastic deformation of the α phase, which is controlled by the glide of type screw dislocations that can be spread in the basal, pyramidal or prismatic planes. The relative stability of these phases depends on the electronic structure of metals. In pure Ti, TEM observations showed that screw dislocations glide in prismatic planes and display an atypical glide mechanism called “jerky motion”. Ab initio simulations showed that this behavior arises from the existence of several structures for the dislocation core. Such mechanisms are highly influenced by the presence of alloying elements. For example, the well-known hardening effect of oxygen is explained by its interactions with the dislocation core which locally forces the dislocation to change glide planes.

Research group The research will be performed at Jean Lamour Institute (IJL), one of the largest materials science institutes in Europe, located in Nancy, France. The student will be part of the Physics, Mechanics and Plasticity team of the Department of Science and Engineering of Materials and Metallurgy. The research will be co-supervised by Lucile Dezerald and Emilie Gaudry (both from IJL) in collaboration with Emmanuel Clouet from CEA Paris-Saclay (France).

Eligible candidate We are looking for a motivated student holding a master degree (or equivalent) in physics, with knowledge in solid-state physics, materials science and/or metallurgy. Experience in coding or atomic scale modeling will be appreciated.

Funding MESR Ph.D. fellowship

Duration 3 years

Starting date October 2017.

Location Jean Lamour Institute, Nancy, FRANCE : http://ijl.univ-lorraine.fr/