Séminaire LGF – Dávid Ugi et Péter D. Ispánovity (ELTE, Hongrie) – 24 novembre 2023

Dávid Ugi et Péter D. Ispánovity sont en visite dans notre laboratoire. A cette occasion, ils délivreront le séminaire suivant.

Intitulé

Plastic deformation of microsamples: Intermittent dislocation avalanches and their acoustic emission

Résumé

On the micrometer scale, deformation properties of metals change profoundly: the smooth and continuous behavior of bulk materials is often replaced by jerky flow due to random strain bursts of various sizes. The reason for this behavior is the complex intermittent redistribution of lattice dislocations due to external loading. This process also leads to the formation of the uneven step-like surface upon deformation. Our highly sensitive micromechanical platform can detect the strain bursts caused by dislocation avalanches in three different ways: (i) by stress and strain measurements using a capacitive displacement sensor measuring the elongation of a spring, (ii) by detection of the emitted acoustic signal using a sensitive piezoelectric transducer and (iii) by visual images using the electron beam of the SEM. In my presentation, I will present two of our recent results obtained with the help of this toolbox.

Biographie

Dávid Ugi is a hungarian research fellow at ELTE, acquired his PhD in 2023. He is specializes in FIB-SEM based analytics, micromechanics and acoustic emission (list of publications).

Péter D. Ispánovity is a hungarian associate professor at ELTE at the Department of Materials Physics. He acquired his habilitation in 2022, and his PhD in 2009. He is the principal investigator on numerous experimental and theoretical projects on micron-scale stochastic deformation phenomena (list of publications).

Eötvös Loránd University (ELTE) is one of the oldest and largest universities in Hungary. It currently has nine faculties, 50 bachelor’s and 120 master’s programmes and 17 doctoral schools. In global university rankings, ELTE is one of the top public universities in Hungary and in the top 5% of higher education institutions worldwide.