Sökning: "defect formation"

Visar resultat 1 - 5 av 225 avhandlingar innehållade orden defect formation.

1. 1. Powder bed fusion processing of Ni-base superalloys - Defect formation and its mitigation

   Författare :Hans Gruber; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; hot isostatic pressing; Ni-base superalloys; non-metallic inclusions; cracking; additive manufacturing; laser powder bed fusion; defect formation; Alloy 718; powder re-use; IN-738LC;

   Sammanfattning : Powder bed fusion of Ni- and Ni-Fe-base superalloys is actively considered a promising manufacturing technology for critical components for the aerospace and industrial gas turbine industries. Such components often operate under harsh conditions, and hence, high demands are placed on both process and feedstock material to meet the strict safety and long-term reliability requirements. LÄS MER

3. 2. ELECTRON BEAM MELTING OF ALLOY 718 - POWDER RECYCLING AND ITS EFFECT ON DEFECT FORMATION

   Författare :Hans Gruber; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; powder recycling; electron beam melting; oxide defects; Alloy 718; defect formation; powder degradation; additive manufacturing; non-metallic inclusions;

   Sammanfattning : As for any production process, the performance of additively manufactured components is ultimately dependent on the quality of the feedstock material. Consequently, for critical components, the feedstock needs to be carefully controlled to assure a stable and reliable quality. LÄS MER

4. 3. In-situ monitoring of laser powder bed fusion applied to defect detection

   Författare :Claudia de Andrade Schwerz; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; defect detection; productivity; nickel-based superalloy; process monitoring; pores; powder bed fusion; spatter; defect mitigation; mechanical properties; lack of fusion; melt pool; Additive manufacturing;

   Sammanfattning : Additive manufacturing technologies, particularly laser powder bed fusion (LPBF), have received much attention recently due to their numerous advantages over conventional manufacturing methods. However, the use of LPBF is still quite restricted, mainly due to two factors: its typically low productivity, which makes the technology less competitive in applications with moderate to high production volumes, and its limited reliability, particularly relevant for applications where high performance is required from the materials. LÄS MER

5. 4. Defect Formation during Solidification in Grey Iron Castings

   Författare :Lennart Elmquist; Ingvar Svensson; Attila Diószegi; Doru Stefanescu; Jönköping University; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Shrinkage Porosity; Grey Iron; Solidification; Nucleation; Primary Austenite; DAAS; Eutectic Cells; Microstructure; Macrostructure; Hot Spot; Oxygen; Hydrogen; Materials science; Teknisk materialvetenskap;

   Sammanfattning : The presence of defects is of major concern in the production of grey iron castings. Some defects are merely an aesthetic problem while others can be detrimental for the performance of the component. Among the several possible defects, shrinkage porosity is one of the more challenging to understand and avoid. LÄS MER

7. 5. Investigations on the Formation of Defect Bands in Semi-Solid High Pressure Die Cast Aluminium-Silicon Alloys

   Författare :Madeleine Law; Pär Jönsson; Christopher Hulme-Smith; Taishi Matsushita; Jessica Elfsberg; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Semi-Solid Metals; SSM; Al-Si Alloys; Defect bands; HPDC; Semisolida metaller; SSM; Al-Si-Alloys; defektband; HPDC; Metallurgical process science; Metallurgisk processvetenskap;

   Sammanfattning : High-pressure die casting of semi-solid aluminium-silicon alloys is used in the automotive industry to manufacture components, like housings, brackets, and bars. It is commonly known that during high-pressure die casting, defect bands may be created that follow the contour of the component surface. These bands consist mainly of a eutectic phase. LÄS MER