Search for dissertations about: "dislocation density"

Showing result 6 - 10 of 64 swedish dissertations containing the words dislocation density.

2. 6. Toward first-principles understanding of carbonitride precipitation in steels

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

   Abstract : 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. READ MORE

4. 7. Dislocation density based material model applied in FE-simulation of metal cutting

   Author : Dan Wedberg; Bevis Hutchinson; Luleå tekniska universitet; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Material Mechanics; Materialmekanik;

   Abstract : Simulation based design enables rapid development of products with increased customer value in terms of accessibility, quality, productivity and profitability. However simulation of metal cutting is complex both in terms of numeric and physics. The work piece material undergoes severe deformations. READ MORE

5. 8. Theoretical studies of boron and transition-metal carbonitride additions in steels

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

   Abstract : 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. READ MORE

6. 9. Numerical Modeling of Plasticity in FCC Crystalline Materials Using Discrete Dislocation Dynamics

   Author : Arash Hosseinzadeh Delandar; Pavel Korzhavyi; Rolf Sandström; Mikko Alava; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Dislocations; crystal plasticity; discrete dislocation dynamics; Cu single crystal; high strain rate deformation; strain rate sensitivity; plastic anisotropy; slip band formation; Teknisk materialvetenskap; Materials Science and Engineering;

   Abstract : Plasticity in crystalline solids is controlled by the microscopic line defects known as “dislocations”. Decisive role of dislocations in crystal plasticity in addition to fundamentals of plastic deformation are presented in the current thesis work. READ MORE

7. 10. Modelling of Dislocation Bias in FCC Materials

   Author : Zhongwen Chang; Pär Olsson; Christophe Domain; KTH; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES;

   Abstract : Irradiation induced void swelling is problematic for the application of austenitic steels under high dose irradiation. In this thesis, the swelling is characterized by dislocation bias. The dislocation bias is obtained using the finite element method, accounting for fcc copper and nickel under electron irradiation. READ MORE