Phase Transformations (PTs) in metals and minerals depend both on temperature and pressure. Phase diagrams, function of pressure and temperature, exist for many materials and allow to know the stable phase of the material for given pressure and temperature conditions.
Experimental evidence suggest that plastic strain and stress (deviatoric) might induce a change on the phases stability. The MULTI-STEP: Multiscale Stress-driven Thermodynamic Equilibrium Predictions project, involving multiple French and German research laboratories, aims at understanding the effect of deviatoric stress on the phase equilibrium of titanium and silica.
To overcome the classical hypotheses for phase equilibrium calculations using a multiscale numerical approach, from atomistic to large-scale thermomechanical modeling, coupled with micromechanical experiments.
In this PhD, results from atomistic simulations (provided by another partner) will be introduced into our multiscale computational mechanics framework at the continuum scale. The methodology will first be developed for the study of PTs in titanium. Then the proposed approach will be applied to the polymorphic quartz-coesite transformation.
