Description:

The Department of Materials Science and Engineering welcomes you to its 2014 Spring Colloquium Series. 

Tuesday, May 6th 
Tech L211, 4:00pm

Pascal Bellon
University of Illinois at Urbana

Plastic Deformation in Alloys:from mixing mechanisms to nanoscale self-organization
Materials are commonly subjected to plastic deformation during fabrication and shaping, and in service. Using analytical models, atomistic simulations, and experiments, our research has shown that metallic alloys subjected to severe plastic deformation display a rich phenomenology, from non-diffusive transport to self-organization at the nanoscale. We predicted in particular that for systems with easy slip transfer across interphase boundaries, the chemical mixing forced by plastic deformation should be superdiffusive. We will present recent experimental work investigating this prediction by subjecting Cu-Ag alloys to high pressure torsion. Another remarkable property of alloys under sustained plastic deformation is their tendency to self-organize, which results from the presence of simultaneous competing processes with distinct intrinsic length scales. We will show that these reactions can be used to design self-adapting materials with improved service properties. This point will be illustrated by showing that, under appropriate conditions, sliding wear can induce nanolayering just below the wear surface, greatly improving wear resistance.

Biography: Professor Bellon received an electrical engineering degree from Ecole Supérieure d'Électricité, France, in 1984 and a PhD in materials science from University Paris 6, France, in 1989. He then worked at the Physical Metallurgy Research Section (SRMP) at the CEA Center for Research at Saclay, France, until 1996. He first worked in the MatSE Department at UIUC as a post-doctoral fellow in 1993-1994, and joined the faculty at UIUC in 1996. He was promoted to Associate Professor in 2002 and Professor in 2009. He received an NSF Career Award in 1998, the Don Burnett Teaching Award in 2000, the Faculty Pierce Award in 2009, and was named a Racheff Faculty Scholar in 2012.