[SY-B4] Symposium B-4

[SY-B4] The complex problem of the experimental validation of atomistic and microstructural evolution models

^○Lorenzo Malerba ( CIEMAT, Energy, Environment and Technology Research Centre, Spain)

The development of physical models for the description of the behaviour of materials under certain conditions goes hands-in-hands with the use of advanced experimental characterization techniques. The experiments provide data and reveal phenomena that the models are expected to predict and explain. The exchange of information between models and experiments is therefore continuous and goes in two directions: models may predict results that need to be verified experimentally and experiments observe processes that the models are expected to reproduce and explain in terms of physical laws and mechanisms. This continuous interplay is often denoted as "experimental validation" of models. While this definition is somewhat restrictive, the validation of models is a discipline in itself that requires first of all the performance of experiments that may be long and expensive, and need to be carefully designed. In addition, the comparison between the results of the models, in particular computer simulations, and the observations from characterization techniques is not always straightforward, because both the experimental and the simulation outcomes need to be properly treated.

In this presentation these problems will be discussed taking the example of the comparison between models that describe the microstructural evolution of iron alloys under irradiation and the results of microstructural characterization techniques such as positron annihilation, small angle neutron scattering, atom probe and transmission electron microscopy.