Sökning: "microhardness"

Visar resultat 1 - 5 av 17 avhandlingar innehållade ordet microhardness.

1. 1. Influence of hydrogen on corrosion and stress induced cracking of stainless steel

   Författare :Ulf Kivisäkk; Christofer Leygraf; Roy Johnsen; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; hydrogen; corrosion; hydrogen embrittlement; stainless steels; uniform corrosion; activation; dewpoint corrosion; low temperature creep; plastic deformation; microhardness; Surface and colloid chemistry; Yt- och kolloidkemi;

   Sammanfattning : Hydrogen is the smallest element in the periodical table. It has been shown in several studies that hydrogen has a large influence on the corrosion and cracking behaviour of stainless steels. Hydrogen is involved in several of the most common cathode reactions during corrosion and can also cause embrittlement in many stainless steels. LÄS MER

3. 2. Fatigue life extension in existing steel bridges. High-Frequency Mechanical Impact treatment and Tungsten Inert Gas remelting in life extension and fatigue crack repair of welded steel structures

   Författare :Hassan al-Karawi; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; HFMI; TIG-dressing; Life extension; Post weld treatment; Gain factor; Linear elastic fracture mechanics; Crack retrofiting; Peening; fatigue crack; Crack detection; Microhardness; Concentration factor; LEFM; TIG-remelting; Strain gauge;

   Sammanfattning : This thesis investigates the performance of improved welds with two post-weld treatment methods for application on existing structures. High-Frequency Mechanical Impact (HFMI) treatment and Tungsten Inert Gas (TIG) remelting were used for fatigue life extension of welded structures. LÄS MER

4. 3. Role of alloying elements in Mo5Si3 intermetallics

   Författare :Erik Ström; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; microhardness; silicide; alloying; ternary; intermetallic; Laves; hardness; high temperature material; Mo5Si3;

   Sammanfattning : The role of alloying elements in the intermetallic compound Mo5Si3 was studied in the alloying systems Mo5-xMxSi3 (M = Cr, Ti, Nb, Ni, or Co, x = 0.5-2). The effects of the alloying elements were examined by characterising the microstructures and identifying the resulting phases. In the case of Cr and Nb alloying, a solubility of 25% (at. LÄS MER

5. 4. TiAlN-based Coatings at High Pressures and Temperatures

   Författare :Robert Pilemalm; Magnus Odén; Mikael Olsson; Rachid M'Saoubi; Mats Jöesaar; Linköpings universitet; []
   Nyckelord :Materials science; thin films; coatings; spinodal decomposition; TiAlN; TiZrAlN; HPHT; high pressure high temperature; BELT-press; transmission electron microscopy; x-ray diifraction; microhardness;

   Sammanfattning : TiAlN and TiAlN-based coatings that are used of relevance as protection of cutting tool inserts used in metal machining have been studied. All coatings were deposited by reactive cathodic arc evaporation using industrial scale deposition systems. The metal content of the coatings was varied by using different combinations of compound cathodes. LÄS MER

7. 5. Additive metallurgy - Thermal influences on structure and properties of stainless steel 316L

   Författare :Jon Olsén; Zhijian James Shen; Dongdong Gu; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Additive manufacturing; Selective laser melting; Electron beam melting; Hot isostatic pressing; Stainless steel; Microstructural heterogeneity; Materials Chemistry; materialkemi;

   Sammanfattning : Additive manufacturing (AM) as a manufacturing process has, in recent years, become widely accepted as capable of manufacturing parts that will be used in end products. In this thesis, stainless steel grade 316L parts are manufactured using two different powder bed fusion techniques, selective laser melting (SLM) and electron beam melting (EBM). LÄS MER