Sökning: "grain coarsening"

Visar resultat 1 - 5 av 20 avhandlingar innehållade orden grain coarsening.

1. 1. Aspects of Structural Evolution in Cemented Carbide – Carbide Size, Shape and Stability

   Författare :Ida Borgh; Joakim Odqvist; Peter Hedström; Annika Borgenstam; Jean-Michel Missiaen; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Cemented carbide; Ti; Zr C; Coarsening; Phase separation; C-activity; initial WC powder size; electron backscattered diffraction; microscopy; X-ray diffraction;

   Sammanfattning : Cemented carbide is a composite material used in applications like cutting tools and rock drilling inserts. The material commonly consists of WC grains embedded in a Co-rich binder phase and the material properties strongly depend on the WC grain size. LÄS MER

3. 2. Neutron scattering studies of hard metals

   Författare :Ahmet Bahadir Yildiz; Peter Hedström; Annika Borgenstam; Joakim Odqvist; Daniele Mari; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Hard metals; cemented carbides; small angle neutron scattering; neutron diffraction; in-situ characterization; grain coarsening; phase separation; Teknisk materialvetenskap; Materials Science and Engineering;

   Sammanfattning : Since their discovery about 100 years ago, tools made of hard metals have been the enablers of development in various areas: from drilling subway lines for more sustainable cities to the machining of complex next-generation airplane engine parts for reduced CO2 emissions. An increase in properties of hard metals thus leads to efficient operations with shorter lead-time, less environmental footprint, and reduced cost. LÄS MER

4. 3. Precipitate stability in creep resistant 9-12% chromium steels

   Författare :Ardeshir Golpayegani; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; growth; precipitates; coarsening; atom probe field ion microscopy APFIM ; energy filtered TEM EFTEM ; 9-12% chromium steel;

   Sammanfattning : 9-12% chromium steels are used extensively in modern steam power plants at service temperatures up to 600°C. These materials are subjected to creep deformation during exposure which is the limiting factor in increasing the steam temperature and thus the thermal efficiency of the plants. 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. Development of a new generation of creep resistant 12% chromium steels: Microstructure of Z-phase strengthened steels

   Författare :Masoud Rashidi; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; phase transformation; CrNbN; impact toughness; Creep; CrTaN; Laves-phase; atom probe tomography; precipitation hardening; M2N; MX; transmission electron microscopy; coarsening;

   Sammanfattning : Fossil-fuel fired steam power plants provide more than 60% of the electricity generated worldwide, and account for about one third of the global CO2 emissions. Increasing the steam temperature and pressure leads to a higher thermal efficiency of the power plants and thus lower emissions. LÄS MER