Abstract
Spheroidisation and oxide disruption phenomena in the direct laser melting of pre-alloyed Al-Mg and Al-Si powders had been explored and interpreted in terms of Raleigh's instability, Marangoni convection, laser absorptivity, heat conductivity, fluidity of the melt volume and the powder's oxide content. Balling occurred only in the single layer parts due to the lower thermal conductivity of the bed and possibly the difference in wettability of the powder bed and sintered layers. The existence of a high degree of thermal expansion mismatch between the oxide film and the parent metal and a uniform oxide layer thickness were found to favour the disruption of the oxide shell promoting inter-particulate melting across the layers. This was the case for Al-Si parts, whereas SLM of pure aluminium and pre-alloyed Al-Mg powders gave rise to high incidence of randomly distributed pores.
Original language | English |
---|---|
Title of host publication | TMS 2009 - 138th Annual Meeting and Exhibition - Supplemental Proceedings |
Pages | 371-380 |
Number of pages | 10 |
Volume | 1 |
Publication status | Published - Oct 5 2009 |
Event | TMS 2009 - 138th Annual Meeting and Exhibition - San Francisco, CA, United States Duration: Feb 15 2009 → Feb 19 2009 |
Other
Other | TMS 2009 - 138th Annual Meeting and Exhibition |
---|---|
Country/Territory | United States |
City | San Francisco, CA |
Period | 2/15/09 → 2/19/09 |
All Science Journal Classification (ASJC) codes
- Condensed Matter Physics
- Mechanics of Materials
- Metals and Alloys