Lee Hsun Lecture Series

Topic: First principles modeling of high-technology alloys

Speaker: Levente Vitos
Applied Materials Physics, Department of Materials Science and Engineering,
Royal Institute of Technology

Time: 10:00-11:30, (Wed.) Jun.14^th, 2017

Venue: Room 468，Lee Hsun Building, IMR CAS

Abstract：

Thanks to the impressive developments within the DFT (Density Functional Theory) based methods, numerical solvers and computational power during the last few decades, modern materials research receives increasing support from first-principles materials modeling. Such approach gives fundamental understanding, offers efficient pre-screening against various degrees of freedom and provides information where experimental assessments are not feasible. Today the ab initio theory-aided materials assay finds its way in almost all areas of advanced materials design and characterization.

Due to the complexity of the problem, for a long time DFT modeling was practically missing within the exciting field of multicomponent alloys such as stainless steels or High Entropy Alloys (HEAs). Starting from the early 2000s, we made a series of attempts to fill this gap and extend the scope of ab initio modeling to high-technology alloys. In my seminar, I will overview the pioneering applications of alloy theory in the case of steels and a few representative HEAs, and point out the main known and hidden challenges associated with such efforts. Our recent progress in predicting the mechanical properties from first-principles theory will be demonstrated for austenitic stainless steels and HEAs composed of 3d metals. Special emphasis will be placed on plastic deformation and intrinsic energy barriers. Finally, I will briefly discuss the possibility of metastable twinning in some special HEAs.