![]()
Gas pores
May arise from powder surface chemistry modification and/or trapped gas in particles that are released during melting and locked in during solidification May also be due to key-hole effect for deep melt pools.
Elongated, non spherical pores [1]
processed induced, due to an inefficient melting regime - either insufficient melting (too little energy input with respect to hatching distance or layer thickness) or spatter and fumes ejection (too much energy input)
Cracking [2, 3]
Due to solidification cracking or grain boundary cracking or other macroscopic effects (macroscopic defects, residual stress, surface roughness, … )
References
[1] W. J. Sames, F. A. List, S. Pannala, R. R. Dehoff & S. S. Babu (2016): The metallurgy and processing science of metal additive manufacturing, International Materials Reviews http://dx.doi.org/10.1080/09506608.2015.1116649 [2] L. N. Carter, M. M. Attallah and R. C. Reed: ‘Laser powder bed fabrication of nickel-base superalloys: influence of parameters; characterisation, quantification and mitigation ofcracking’, in ‘Superalloys 2012’, (ed. Eric S. Huron et al.), 577– 586; 2012, Champion, PA, John Wiley & Sons, Inc. [3] TWI. What is hot cracking (solidification cracking)?, 2015. Available at http://www.twi-global.com/technical-knowledge/faqs/material-faqs/faq-what-is-hot-cracking-solidification-cracking/ [4] K. Kempen, L. Thijs, B. Vrancken, S. Buls, J. Van Humbeeck and J.-P. Kruth: ‘Producing, crack-free, high density M2 HSS parts by selective laser melting: pre-heating the baseplate’, in ‘Solid freeform fabrication symposium’, Austin, TX, 2013. [5] K. Kempen, L. Thijs, B. Vrancken, S. Buls, J. Van Humbeeck and J.-P. Kruth: ‘Producing, crack-free, high density M2 HSS parts by selective laser melting: pre-heating the baseplate’, in ‘Solid freeform fabrication symposium’, Austin, TX, 2013. [6] J. A. Manriquez-Frayre and D. L. Bourell: ‘Selective laser sintering of binary metallic powder’, in ‘Solid freeform fabrication symposium’, Austin, TX, 1990, 99–106. [7] Di Wang, Yongqiang Yang, Ziheng Yi, Xubin Su, Research on the fabricating quality optimization of the overhanging surface in SLM process, The International Journal of Advanced Manufacturing Technology April 2013, Volume 65, Issue 9, pp 1471-1484
0 Comments
Your comment will be posted after it is approved.
Leave a Reply. |
We provide practical and actionable info dedicated to additive manufacturing of high-value metal components
Categories
All
|