Laser powder bed fusion of in-situ composites using dry-mixed Ti6Al4V and Si3N4 powder. (November 2020)

• Record Type: Journal Article
• Authors: Akilan, Arulselvan Arumugham; Gökçe, Azim; Nath, Subrata Deb; Balla, Vamsi Krishna; Kate, Kunal H.; Atre, Sundar V.
• Is Part Of: Journal of manufacturing processes. Volume 59(2020)
• Page Start: 43
• Page End: 50
• Publication Date: 2020-11
• Subjects: Laser powder bed fusion (L-PBF) -- In-situ composites -- Metal matrix composites (MMC) -- Microstructure -- Titanium alloys; Production management -- Data processing -- Periodicals; Manufacturing processes -- Periodicals; Procestechnologie; Productietechniek; Production -- Gestion -- Informatique -- Périodiques; Fabrication -- Périodiques; Manufacturing processes; Production management -- Data processing; Periodicals; 670.5
• DOI: 10.1016/j.jmapro.2020.09.027
• Languages: English
• ISSNs: 1526-6125

Abstract

Graphical abstract: Abstract: Herein, we report laser powder bed fusion (L-PBF) of dry-mixed Ti6Al4V + Si3 N4 powder to create in-situ titanium matrix composites. The dry-mixed Ti6Al4V powder with 5 wt.% Si3 N4 was processed using l -PBF at varying laser energy densities, between 44 and 133 J/mm 3, by changing the laser scan speed (400–1200 mm/s) at constant laser power of 96 W, layer thickness of 20 μm and scan spacing of 90 μm. The selected samples were examined for microstructural evolution, in-situ reaction products and hardness. The results showed that the in-situ reaction between liquid titanium and Si3 N4 forms fine TiN and Ti5 Si3 reinforcements in these l -PBF processed samples. However, the irregular shape and fine size of Si3 N4 reduced the feedstock flowability, and the composites could not be processed with laser energy density (E) < 89 J/mm 3 . The amount, distribution and size of the reinforcements were found to depend on the laser energy density. These in-situ composites exhibited high hardness of 860 ± 49 KHN, which is 110 % higher than that of Ti6Al4V and ex-situ processed Ti-TiN and Ti-TiC composites. Our results show that the dry-mixed Ti6Al4V-Si3 N4 feedstock can be processed using l -PBF but further improvement is required through adjusting Si3 N4 powder attributes (size, shape) and concentration.