Change search
ReferencesLink to record
Permanent link

Direct link
A study of micro- and surface structures of additive manufactured selective laser melted nickel based superalloys
KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering.
2016 (English)Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
Abstract [en]

This study examined the micro- and surface structures of objects manufactured by selective laser melting (SLM). The results show that the surface roughness in additively manufactured objects is strongly dependent on the geometry of the built part whereas the microstructure is largely unaffected.

As additive manufacturing techniques improve, the application range increases and new parameters become the limiting factor in high performance applications. Among the most demanding applications are turbine components in the aerospace and energy industries. These components are subjected to high mechanical, thermal and chemical stresses and alloys customized to endure these environments are required, these are often called superalloys.

Even though the alloys themselves meet the requirements, imperfections can arise during manufacturing that weaken the component. Pores and rough surfaces serve as initiation points to cracks and other defects and are therefore important to consider.

This study used scanning electron-, optical- and focus variation microscopes to evaluate the microstructures as well as parameters of surface roughness in SLM manufactured nickel based superalloys, Inconel 939 and Hastelloy X. How the orientation of the built part affected the surface and microstructure was also examined. The results show that pores, melt pools and grains where not dependent on build geometry whereas the surface roughness was greatly affected. Both the Rz andRa values of individual measurements were almost doubled between different sides of the built samples. This means that surface roughness definitely is a factor to be considered when using SLM manufacturing. 

Place, publisher, year, edition, pages
2016. , 26 p.
Keyword [en]
additive manufacturing, selective laser melting, microstructure, surface roughness, superalloy
National Category
Materials Engineering Metallurgy and Metallic Materials
URN: urn:nbn:se:kth:diva-188154OAI: diva2:933717
External cooperation
Siemens Industrial Turbomachinery AB
Subject / course
Chemical Engineering
Educational program
Master of Science in Engineering - Materials Design and Engineering
2016-05-20, Jernkontoret, Kungsträdgårdsgatan 10, Stockholm, 12:05 (English)
Available from: 2016-09-16 Created: 2016-06-07 Last updated: 2016-09-16Bibliographically approved

Open Access in DiVA

fulltext(3479 kB)30 downloads
File information
File name FULLTEXT01.pdfFile size 3479 kBChecksum SHA-512
Type fulltextMimetype application/pdf

By organisation
Materials Science and Engineering
Materials EngineeringMetallurgy and Metallic Materials

Search outside of DiVA

GoogleGoogle Scholar
Total: 30 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Total: 69 hits
ReferencesLink to record
Permanent link

Direct link