Sökning: "semicoherent interfaces"

Visar resultat 1 - 5 av 7 avhandlingar innehållade orden semicoherent interfaces.

1. 1. Multiscale Modeling of Interfaces

   Författare :Sven Johansson; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; misfit; Peierls-Nabarro model; semicoherent interfaces; interfaces; cemented carbides; grain boundaries; microstructure; VN precipitates; density-functional theory;

   Sammanfattning : Understanding strength and stability of interfaces between dissimilar materials or phases is a highly active field of contemporary materials research. Knowledge of interface structure and energetics is important for modeling of complex materials both on a mechanical and thermodynamical level as well as for many functional properties. LÄS MER

3. 2. A computational study of interface structures and energetics in cemented carbides and steels

   Författare :Sven Johansson; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; WC-Co; cemented carbides; interfaces; density functional theory; microstructure; sintering; steels;

   Sammanfattning : Cemented carbides are hard composite materials of great industrial importance. Because of their combination of hardness and toughness, they are used e.~g. for cutting, drilling, turning and milling. LÄS MER

4. 3. Theoretical studies of boron and transition-metal carbonitride additions in steels

   Författare :Dan Fors; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Electronic structure; Dislocation network; Interfaces; Peierls-Nabarro model; Density functional theory; Steels; Coarsening; Diffusion; Misfit; Precipitates;

   Sammanfattning : Martensitic 9-12%Cr steel alloys are today widely used as critical components in fossil-fired steam power plants with steam temperatures up to 600°C, where sound oxidation resistance and excellent creep strength are required. Their strength and long-term creep resistance are closely connected to the presence and stability of Cr-rich M23C6 (M = Cr, Fe) carbides and densely distributed MX precipitates (M = transition metal, X = C or N), which effectively act as obstacles for dislocation migration. LÄS MER

5. 4. Toward first-principles understanding of carbonitride precipitation in steels

   Författare :Dan Fors; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Steels; Coarsening; Interfaces; Peierls-Nabarro model; Diffusion; Precipitates; Density functional theory; Dislocation network; Misfit; Electronic structure;

   Sammanfattning : The most important and widely used group of metallic alloys is steels, whichare alloys of the element iron together with carbon and usually other elementssuch as B, N, V, Nb and Cr. The strength in these alloys is closely connectedto the distribution of point defects, precipitates and grain boundaries whicheffectively act as obstacles for dislocation migration. LÄS MER

7. 5. First-principles investigations of planar defects

   Författare :Lu Song; Levente Vitos; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

   Sammanfattning : Two types of planar defects, phase interface and stacking fault, are addressed in this thesis. The investigation is mainly carried out for stainless steels which are fundamental materials in modern society. For the phase interface, we investigate the metallic bcc/bcc and fcc/bcc phase interfaces. LÄS MER