Since recently, Molybdenum has been considered as a material of interest in many dynamic configurations, especially in Defense applications such as for shaped charge liners, where extreme dynamic loadings (high strain rates, large strains, high pressures …) are encountered. Nonetheless, this material has been essentially characterized through quasi-static experiments or under extreme pressures related to planetology issues for instance.
At the meantime, laser shock experiments have gained in importance. Indeed, compared to other dynamic loading techniques (impacts, explosives …), laser-driven shocks offer a large loading range capability (by varying intensity, size and duration of the laser pulse), some insight into the plastic behavior of the materials at extremely high strain rates, and easy sample recovery for a variety of post-mortem analyses.
The main objective of this PhD, co-supervised by Institut Pprime (CNRS, ISAE-ENSMA) in Poitiers (France), is to characterize the behavior of laser shock-loaded Molybdenum over a range of loads representative of shaped charges, to test and to improve whenever possible the predictive capabilities of existing models. Innovative configurations will be studied.
For that purpose, the student will have to design, to carry out and post-process various laser shock experiments so as to :
- Characterize the elasto-plastic behavior of Molybdenum through time-resolved velocity measurements and possibly temperature measurements ;
- Realize post-mortem analyses on Molybdenum specimens ;
- Analyze the implosion phase representative of what generates shaped charges jets on notched specimens ;
- Analyze the effects of inclined shocks on Molybdenum.