Sökning: "Teknisk fysik med inriktning mot materialvetenskap"

Visar resultat 31 - 35 av 56 avhandlingar innehållade orden Teknisk fysik med inriktning mot materialvetenskap.

1. 31. Workpiece steels protecting cutting tools from wear : A study of the effects of alloying elements on material transfer and coating damage mechanisms

   Författare :Toshiharu Aiso; Staffan Jacobson; Urban Wiklund; Staffan Söderberg; Uppsala universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Metal cutting; Steel; Cutting tools; Transfer; Coating; Sliding; Teknisk fysik med inriktning mot tribomaterial; Engineering Science with specialization in Tribo Materials;

   Sammanfattning : The vision of this thesis is to improve the machinability of workpiece steels. Workpiece material frequently transfers to the cutting tools during machining, and the transfer layers then forming on the tools may give both good and bad effects on machining performance and tool life. LÄS MER

3. 32. Protective Tribofilms on Combustion Engine Valves

   Författare :Robin Elo; Staffan Jacobson; Mikael Åstrand; Uppsala universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Internal combustion engine; valve; sealing surface; tribofilm; oil residue; test rig; Teknisk fysik med inriktning mot tribomaterial; Engineering Science with specialization in Tribo Materials;

   Sammanfattning : Inside the complex machinery of modern heavy-duty engines, the sealing surfaces of the valve and valve seat insert have to endure. Right next to the combustion, temperatures are high and high pressure deforms the components, causing a small relative motion in the interface. LÄS MER

4. 33. Galling of high strength steels and stainless steels in sheet metal forming as evaluated using pin-on-disc testing

   Författare :Jenny Eriksson; Mikael Olsson; Uppsala universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Galling; sheet metal forming; high strength steels; stainless steels; Teknisk fysik med inriktning mot tribomaterial; Engineering Science with specialization in Tribo Materials;

   Sammanfattning : The thesis focuses on the problem galling in sheet metal forming operations. Galling occurs when sheet metal transfers from the sheet surface onto the tool surface and causes surface damages to following sheets in the forming operation. When this happens the tool must be replaced causing production stops and additional expenses. LÄS MER

5. 34. Microstructural, Mechanical and Tribological Characterisation of CVD and PVD Coatings for Metal Cutting Applications

   Författare :Mikael Fallqvist; Staffan Jacobsson; Mikael Olsson; Uppsala universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Tribology; Friction; Wear; Coatings; CVD; PVD; Alumina; Metal cutting; Teknisk fysik med inriktning mot tribomaterial; Engineering Science with specialization in Tribo Materials; Steel Forming and Surface Engineering;

   Sammanfattning : The present thesis focuses on characterisation of microstructure and the resulting mechanical and tribological properties of CVD and PVD coatings used in metal cutting applications. These thin and hard coatings are designed to improve the tribological performance of cutting tools which in metal cutting operations may result in improved cutting performance, lower energy consumption, lower production costs and lower impact on the environment. LÄS MER

7. 35. Combustion Valve Wear : A Tribological Study of Combustion Valve Sealing Interfaces

   Författare :Peter Forsberg; Staffan Jacobson; Rob Dwyer-Joyce; Uppsala universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Combustion valves; wear; tribofilm; test rig; combustion residue; Teknisk fysik med inriktning mot tribomaterial; Engineering Science with specialization in Tribo Materials;

   Sammanfattning : The exhaust valve system of combustion engines experiences a very complex contact situation of frequent impact involving micro sliding, high and varying temperatures, complex exhaust gas chemistry and possible particulates, etc. In addition, the tribological situation in the exhaust valve system is expected to become even worse due to strict future emission regulations, which will require enhanced combustion and cleaner fuels. LÄS MER