Title:	Atomic Scale Modeling of Alloys and Functional Materials
DNr:	SNIC 2014/1-238
Project Type:	SNIC Medium Compute
Principal Investigator:	Paul Erhart <erhart@chalmers.se>
Affiliation:	Chalmers tekniska högskola
Duration:	2014-08-01 – 2015-08-01
Classification:	10304
Homepage:	http://fy.chalmers.se/~erhart
Keywords:

Abstract

I. Metallic alloys are highly versatile materials with applications in almost every area of modern technology. Their properties are strongly dependent on the internal structure of the material and can be modified dramatically both by heat and mechanical treatments. Our objective is to develop models and tools for simulating concentrated multi-component alloys on the atomic scale that will enable an improved understanding of the microscopic processes that govern materials response on the macroscopic scale. Specifically we target W and Ti-based alloys with respect to applications in fusion reactors and lightweight construction, respectively. With regard to W-alloys we aim to perform a quantitative study of the effect of different substitutional alloying elements, most notably Ti and Re, on screw dislocation climb. This project is carried out in collaboration with Prof. J. Marian at the University of California, Los Angeles and Dr. A. Stukowski at Technische Universität Darmstadt, Germany. In the coming year we plan to investigate the W-Ti system across the entire concentration range. Using first-principles calculations we are going to obtain parameters for a set of effective models that will enable us to predict the full phase diagram. In addition we will develop an interatomic potential that will be suitable for studying for example plastic deformation at the atomic scale. In this context we will also carry out extensive atomistic simulation using molecular dynamics and Monte Carlo simulation codes. We will also continue our research regarding the effect of oxygen on Ti-alloys with an emphasis on the formation of suboxide precipitates and their effect on mechanical properties. To this end, we plan to carry out a combination of first-principles calculations and Monte Carlo simulations on the basis of cluster expansions. This project is carried out in collaboration with the research group of Prof. Mark Asta at the University of California in Berkeley. II. Understanding and manipulating the thermal conductivity of materials is of interest to a large number of applications, including thermal management in electronic devices, thermoelectric energy generation as well as active cooling, just to name a few. In collaboration with experimental groups at Chalmers we are studying thermal conductivity and its dependence on microstructure with an emphasis on thermoelectric materials. In this context we plan to continue our investigations on the basis of extensive first-principles calculations regarding the electronic and vibrational (phononic) structure of various materials, including for example inorganic clathrates, silicides, selenides, and sulfides. In addition we will increasingly use parametrized models for studying anharmonicity in these systems based on code developed over the course of the last two years in our group. To this end, we will employ solvers for the Boltzmann transport equation as well as direct atomistic simulations, both of which strongly benefit from large scale resources and can take advantage of parallelization.