Resumen:

Titanium alloys are widely employed in aerospace applications owing to superior properties such as a high specific strength and a good corrosion resistance. In particular, the variety of dual phase microstructures obtained through different thermo-mechanical processing routes enables tailoring of mechanical properties. Pioneering studies have rationalized relationships between microstructures and mechanical properties using the concept of effective slip length, which corresponds to the mean free path for dislocation glide. However, a quantitative prediction of mechanical properties remains elusive for heterogeneous microstructures such as those found in engineering components. In this presentation, we report clarifications of the role of the microstructure in the mechanical behavior of Ti alloys subjected to monotonic and cyclic loadings. Deformation was studied in relation to the microstructure with an emphasis on configurations leading to strain localization. Specific approaches including in situ DIC, large scale EBSD mapping and FFT-based crystal plasticity simulations were employed to consider representative regions. In addition, the identification of damage mechanisms was undertaken to clarify the interplay between heterogeneous deformation and critical microstructure arrangements. New insights into an improved understanding of relationships between the microstructure and the mechanical properties in Ti alloys are illustrated using different examples.

Biografía:

Samuel Hemery es profesor asistente en el Instituto Pprime e ISAE-ENSMA Poitiers (Francia) desde 2014. Tras cursar estudios de ingeniería, realizó una tesis doctoral en ciencia de los materiales (2013) en la Escuela Central de París. Sus primeros trabajos se centraron en la fragilización por metal líquido de aceros en NA líquido para reactores rápidos en CEA. Sus intereses de investigación actuales se centran principalmente en las aleaciones de Ti empleadas en aplicaciones aeroespaciales. Esto incluye el análisis de los mecanismos implicados en la deformación y la fractura. Se presta especial atención al comportamiento de las aleaciones de Ti sometidas a cargas de fatiga y de permanencia-fatiga. Las relaciones entre la microestructura y las propiedades mecánicas se examinan utilizando diferentes técnicas de caracterización (SEM, EBSD, DIC, ensayos in situ) y simulación (CP-FFT). También es editor adjunto de Metallurgical and Materials Transactions A (Key Reader) desde 2017.