SNIC
SUPR
SNIC SUPR
Ab initio bases modeling of defects and disorder in engineering materials
Dnr:

SNIC 2017/1-643

Type:

SNAC Medium

Principal Investigator:

Pavel Korzhavyi

Affiliation:

Kungliga Tekniska högskolan

Start Date:

2018-01-01

End Date:

2019-01-01

Primary Classification:

20506: Metallurgy and Metallic Materials

Secondary Classification:

10402: Physical Chemistry

Tertiary Classification:

10304: Condensed Matter Physics

Allocation

Abstract

The planned multi-disciplinary research studies are related to several active projects funded by National Research Foundations: - Hierarchic Engineering of Industrial Materials "Hero-m 2 Innovation" (Vinnova Competence Center 2016-00668), 2017-2022. Funding source: VINNOVA, Swedish Industry, and KTH; - "Atomistic simulations of thermal and chemical oxidation of Al metal and Al-based alloys" (CTS 16: 253), 2017-2018, Carl Tryggers Stiftelse för Vetenskaplig Forskning. These as well as several shorter-term research projects are partly financed by and involving industrial partners such as Thermo-Calc Software, Sandvik Coromant, SKB, and Sapa Technology. The project is concerned with theoretical and computational studies of defects (ranging from 0D point defects such as vacancies and impurities to 2D planar defects such as surfaces and interfaces), defect interactions, and defect arrangements in the main phases of industrially relevant materials such as steels, aluminum and copper alloys, and ceramic materials. These studies are to provide data on the atomic-level structures and mechanisms that are important for understanding and controlling the thermodynamic, mechanical, and kinetic properties of the studied materials. We adopt an integrated computational modeling approach based on quantum mechanics and statistical physics, starting from electronic and atomic levels and passing the data to semi-discrete and continuum methods that operate at longer length- and time-scales. Within this approach, we have developed efficient theoretical tools for describing the thermodynamic and kinetic properties of materials at elevated temperatures. These methods enable computer-aided optimization of the compositions and the heat treatment of new grades of steel, superalloys, and refractory ceramics, in order adapt these materials to novel applications in which an unusual combination of properties may be required. The research plan involves the following work packages (WPs): WP-1: Alloy phases Task 1.1: Ab initio based atomistic modeling studies of solute interactions and ordering in Fe-based (fcc and bcc) solid solutions. Task 1.2: Calculations of the physical properties of end member compounds for the compound energy models of bcc and fcc solid solutions of industrially relevant chemical elements (d- transition metals, sp- metals and metalloids). Task 1.3: Case studies of the electronic and atomic structure of complex intermetallic and metal-metalloid compounds, e.g., topologically close-packed (TCP) phases in Co-Cr and Co-W systems, Ni-Mn-Si-rich phases wuch as the G-phase, transition metal carbides, nitrides, and oxides. WP-2: Lattice defects Task 2.1: Systematic studies of point defects (impurities, vacancies, intersititials, and their clusters) and their diffusion in alloys and compounds. Task 2.2: Modeling of the structure and dynamics of extended lattice defects (coherent and semi-coherent interfaces, interphase boundaries) in metals and alloys. Task 2.3: Ab initio based multi-scale modeling studies of segregation phenomena at selected phase interfaces and high-angle grain boundaries. Analysis of the possible effect of segregating elements on the precipitate structure and grain boundary cohesion in Al-, Cu-, and Fe-based alloys.