Axis 2 : KNOWLEDGE BASED DESIGN

Functional properties of material surfaces | Intrinsic properties of materials | Control of surface processing | Surface sustainability | Tribology | Surface reactivity | Surface mechanics | Prediction, modeling | Surface, interface, environment | Tailoring surface properties | Surface processing technology | Physics and mechanics of materials

This axis uses an inductive approach, starting from the final application to understand the fundamental phenomena that occur at surface scales (contact, reactivity, chemical and mechanical coupling...). This approach requires the addition of a modeling approach.

The generic questions tackled by this axis are :

• Which intrinsic properties of a material and its surface need to be optimized to achieve the required functional properties ?
• How to control and optimize production processes and their induced effects on surfaces ?

The axis has three unifying topics :

This topic is a strong point of LABEX laboratories, most of which have conducted extensive research in this field.

DLC coating on the femoral head of a hip prosthesis	Stress distribution in a coating, induced by sliding contact

This research axis is a common point of interest for the different laboratories belonging to Manutech-SISE. It is closely linked to “Tribologically Transformed Structures” induced by sliding tests, surface nano-crystallization induced by mechanical surface treatments or the unwanted machining induced white layer. Despite the different terms used, the underlying physical phenomena are almost the same (severe plastic deformation, high strain rate, high temperature), and are mainly related to the dynamic recrystallization/restauration ability of surfaces when they are subject to severe contact loadings. These modified zones can seriously affect surface reactivity, fatigue life and more generally, the sustainability of engineering parts. There is thus an urgent need for industrial renewal which will open interesting research into ways to tailor surfaces without using additional coatings or thermochemical treatments.

Machining-induced white layer	Surface nano-cristallization induced  by severe shot peening

This is as an emerging research topic, with a few studies by LABEX members to date that have attracted both academic and industrial interest. It concerns both the functionalization of polymers and coatings by processes compatible with low temperature deposition (sol-gel, Dynamic Chemical Plating...).

Texturing of polypropylene using a femtosecond laser (PhD thesis- V Belaud LTDS-ECL)