Sökning: "Microstructure Evolution"

Visar resultat 26 - 30 av 148 avhandlingar innehållade orden Microstructure Evolution.

1. 26. Palaeobiology and diversification of Proterozoic-Cambrian photosynthetic eukaryotes

   Författare :Heda Agić; Małgorzata Moczydłowska; Shuhai Xiao; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; microfossils; eukaryotes; Mesoproterozoic; Neoproterozoic; Cambrian; Ordovician; palaeobiology; biostratigraphy; phylogeny; China; Estonia; Siberian Platform; prasinophytes; microstructure; Raman spectroscopy; Earth Science with specialization in Historical Geology and Palaeontology; Geovetenskap med inriktning mot historisk geologi och paleontologi;

   Sammanfattning : One of the most important events in the history of life is the evolution of the complex, eukaryotic cell. The eukaryotes are complex organisms with membrane-bound intracellular structures, and they include a variety of both single-celled and multicellular organisms: plants, animals, fungi and various protists. LÄS MER

3. 27. Formation of Bainite Studied by In-situ High-energy X-ray Diffraction

   Författare :Sen Lin; Peter Hedström; Annika Borgenstam; Sébastien Allain; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Steel; Bainitic transformation; High-energy X-ray diffraction; Electron microscopy; Carbon diffusion; Thermodynamics and kinetics; Microstructure evolution; 高强钢; 贝氏体转变; 原位高能X射线衍射; 扫描与透射电子显微镜; 碳扩散; 热力学与动力学; 微观结构表征; Stål; Bainitiska fasomvandlingen; Högenergi-röntgendiffraktion; Elektronmikroskopi; Koldiffusion; Termodynamik och kinetik; Mikrostrukturutveckling; Materials Science and Engineering; Teknisk materialvetenskap;

   Sammanfattning :       Bainitic steels have attracted great attentions in recent years due to their excellent combination of properties to accommodate a wide range of applications. A deep and comprehensive understanding of how bainite forms is required to better design the production process and optimize the properties of bainitic steels. LÄS MER

4. 28. Creep modelling of particle strengthened steels

   Författare :Hans Magnusson; Rolf Sandström; Wolfgang Blum; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; creep rate modelling; particle hardening; microstructure evolution; dislocation climb; ferritic steels; Materials science; Teknisk materialvetenskap;

   Sammanfattning : Materials used in thermal power plants have to resist creep deformation for time periods up to 30 years. Material evaluation is typically based on creep testing with a maximum duration of a few years. This information is used as input when empirically deriving models for creep. LÄS MER

5. 29. Study of precipitation in martensitic Fe-C-Cr alloys during tempering : Experiments and modelling

   Författare :Ziyong Hou; Joakim Odqvist; Andersson Jörgen; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Fe-C-Cr alloy; Microstructure; Precipitates; Tempering of martensite; Electron microscopy; Modelling.; Teknisk materialvetenskap; Materials Science and Engineering;

   Sammanfattning : Understanding the precipitation reaction is very important since precipitation hardening is one of the most effective strengthening mechanisms in metallic alloys. In martensitic steels, a tempering heat treatment is often performed. LÄS MER

7. 30. Evolution of Microstructure in Two Austenitic Alloys at High Temperatures

   Författare :Jenny M Erneman; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; N ; Thermo-Calc; Nb C; gamma prime; DICTRA; APFIM; quantitative metallography; AISI 347; Alloy 800; energy filtered TEM; sigma phase;

   Sammanfattning : A niobium stabilised AISI 347 austenitic stainless steel was investigated after static ageing and creep deformation at temperatures between 500°C and 800°C for times up to 88 000 h. Coarse and fine NbX precipitates and also s-phase precipitates were formed in the temperature range 500-700°C. LÄS MER