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Revealing Structural Defects Governing the Plastic Deformation of Colloidal Glasses

by Dr. Vijaykumar Chikkadi, IISER Pune

Seminar Hall 31, 2nd Floor, Main Building

Abstract :

Defects control the mechanical properties of materials. In 1934, E. Orowan, M. Polanyi, and G.I. Taylor proposed that macroscopic deformation in crystalline materials originates from the dynamics of defects, which are easily identifi able from the lattice distortions. However, in amorphous solids, the absence of long-range order makes detecting defect-like regions signifi cantly more challenging. While various methods have been proposed to identify soft, defect-like regions in disordered solids that are susceptible to failure under external stress, direct observation in experimental systems has proven diffi cult. In this talk, I will present experimental studies on colloidal glasses, demonstrating that macroscopic deformation in amorphous materials originates from the irreversible rearrangement of particles in regions with structural defects.

 

Reference : R. Sahu, M. Sharma, P. Schall, S. Bhattacharyya, V. Chikkadi, Structural origin of relaxation in dense colloidal suspensions, PNAS (2024).