Topic: An atomic-level perspective of deformation behaviour of metallic glasses 

Speaker: Dr. Daniel Sopu 

Erich Schmid Institute of Materials Science, Austrian Academy of Sciences 

Time: 10:00-11:30, Sept. 25 (wed.), 2019 

Venue: Room 468, Lee Hsun Building, IMR CAS 

Abstract: 

The structural disorder of metallic glasses (MGs) entails the absence of structural features such as grain and phase boundaries, dislocations, and stacking faults. Because of this, MGs can reach yield strengths close to the theoretical limit and large elastic strains. However, the structure-property relationships are experimentally challenging to investigate because of the amorphous nature of MGs and the spatial and temporal scales of the deformation processes. The currently accessible sample sizes and timescales of molecular dynamics (MD) simulations are ideal for studying the atomic structure and deformation behaviour of MGs. In this talk I will provide an overview focused exclusively on importance of MD simulations in the investigation of structure-property relationships in metallic glasses. First, I will present a novel atomic-scale mechanism underlying shear band formation in MGs. After, valuable insights about the interplay of extrinsic size effects and plastic behavior of nanoscaled MGs will be provided. Finally, the observed enhanced plasticity in composite MGs with crystalline heterogeneities will be elucidated and the correlation between crystalline inclusions volume fraction, phase or forms and the variation in the deformation mechanisms will be investigated.  

Brief biography: 

Dr. Daniel Sopu worked on MD simulations in the group of Prof. K. Albe at TU Darmstadt, Germany, where he received his PhD in 2011. During his PhD study, he have investigated the structure and properties of nanoscaled metallic glasses (nanoglasses) working in close collaboration with Prof. H. Gleiter and Prof. H. Hahn from the Karlsruhe Institute of Technology. Later, he held a postdoctoral position at the Interdisciplinary Centre for Advanced Materials Simulation (ICAMS) in Bochum, Germany, where he developed and optimized a transition path sampling method to determine two of the key quantities in solidification, the solid-liquid interface energy and velocity. In 2014, he joined the group of Prof. J. Eckert at IFW Dresden in Germany, and he was responsible with modeling and simulation approaches necessary to support the experimental results. In 2017, he moved to Leoben, Austria and joined the Erich Schmid Institute (ESI) of Materials Science. Now he is the leader of the atomistic modeling group.