| 1. |
- Li, Kailun, et al.
(författare)
-
Crack suppression in additively manufactured tungsten by introducing secondary-phase nanoparticles into the matrix
- 2019
-
Ingår i: International journal of refractory metals & hard materials. - : Elsevier BV. - 0263-4368. ; 79, s. 158-163
-
Tidskriftsartikel (refereegranskat)abstract
- In this study, an effective strategy was developed to suppress cracking by introducing secondary-phase ZrC nanoparticles into a tungsten (W) matrix. Pure W and W-0.5wt%ZrC bulks were additively manufactured via the laser powder bed fusion (LPBF) technique, and their cracking behaviour was compared. It was observed that the crack density of W-ZrC was reduced by 88.7% compared with that of pure W. The grains in W-ZrC were obviously refined compared with the grains in pure W, which significantly increased the cracking resistance. In addition, ZrC diminished the oxygen impurities, further increasing the cracking resistance. This study provides a promising strategy for the additive manufacturing of high-quality W by introducing secondary-phase nanoparticles into the metal matrix.
|
|
| 2. |
- Wang, Dianzheng, et al.
(författare)
-
Cracking in laser additively manufactured W : Initiation mechanism and a suppression approach by alloying
- 2019
-
Ingår i: Materials & design. - : Elsevier BV. - 0264-1275 .- 1873-4197. ; 162, s. 384-393
-
Tidskriftsartikel (refereegranskat)abstract
- Cracking represents the main challenge for exploiting tungsten in additive manufacturing. In this study, laser powder-bed-fusion technique was applied to additively manufacture tungsten. In the built bulks, the grain boundaries were found to be rich in nanoscale gas pores. On the basis of that, a nanopore segregation induced cracking initiation mechanism was proposed. In order to control cracks, W-6wt.%Ta alloy was produced and the cracking suppression mechanism was investigated. The W-6Ta alloy is characterized by a submicron intragranular cellular structure, which composed large amount of interlocked dislocations as revealed by transmission electron microscopy. Owing to the cellular structure, the nanopores were trapped inside grains, which can reduce the cracking possibility. Moreover, the W-Ta alloy possesses higher strength (by 17%) and higher energy dissipation rate (by 52%) than pure tungsten, which both are beneficial for crack reduction.
|
|
