Pure tungsten and oxide dispersion strengthened tungsten manufactured by selective laser melting: Microstructure and cracking mechanism

The microstructure and cracking behavior of pure tungsten and micron- and nanosized Y 2 O 3 dispersion strengthened tungsten fabricated by selective laser melting are comparatively studied in this work. The pure tungsten with high density (98.3 ± 0.3 %) is successfully fabricated by optimizing processing parameters, but there are still a few microcracks. The cracking mechanism of pure tungsten is attributed to the segregation of tungsten oxide impurities at the grain boundaries and the formation of high-angle grain boundaries. The agglomeration of Y 2 O 3 occurs only in the tungsten with the addition of micron-Y 2 O 3 while not in the tungsten with the addition of nanosized Y 2 O 3 . The addition of Y 2 O 3 can reduce cracks due to the formation of a large number of low-angle twisted tungsten grains. The cracking mechanism of pure tungsten and the inhibition of cracking by the addition of Y 2 O 3 proposed in this work are of great significance for the SLM manufacture of high-performance and crack-free tungsten-based alloys. Our work may also provide relevant strategy for the suppression of crack in other alloys with high melting point by SLM.