Tungsten Heavy Alloys from Mixed Feedstock by RF Plasma

0581973 - ÚFP 2024 RIV DE eng J - Journal Article
Kovarik, O. - Čížek, Jan - Klečka, Jakub - Karlík, M. - Čech, J. - Kozlík, J. - Lauschmann, H.
Tungsten Heavy Alloys from Mixed Feedstock by RF Plasma.
Journal of Thermal Spray Technology. Roč. 32, č. 8 (2023), s. 2747-2762. ISSN 1059-9630. E-ISSN 1544-1016
R&D Projects: GA MŠMT EF16_019/0000778; GA ČR(CZ) GA19-14339S
Institutional support: RVO:61389021
Keywords : additive manufacturing * fatigue crack growth rate * fracture toughness * inert atmosphere * stress-strain
OECD category: Materials engineering
Impact factor: 3.1, year: 2022
Method of publishing: Limited access
https://link.springer.com/article/10.1007/s11666-023-01647-6

Tungsten heavy alloys (WHA) are particulate composites of spherical W particles embedded in a ductile Ni-rich matrix. In our study, pre-treated W and Ni feedstock powders were used to prepare three different compositions (all wt.%) for spraying: W-10Ni, W-20Ni for two different WHA, and W-65Ni for a matrix-only material without the reinforcing W particles. Using radio frequency inductively coupled plasma spraying (RF-ICP) method, low porosity deposits were obtained with ductility exceeding 5%. By a detailed study of the microstructure and the particle-matrix interfaces, the mechanism of the composite formation was identified: a rapid dissolution of W in the liquid Ni and a subsequent W particle solidification followed by the solidification of the matrix. The mechanical properties of the composites are defined by the Ni-rich matrix (tough and significantly stronger than pure Ni) with well bonded stiff W particles. The elastic behavior was related to the W content following the Reuss model, describing a layered composite modulus in a serial configuration. Contrary to this, in the plastic regime, all WHA exhibited nearly identical behavior regardless of the W content. In this regime, the deformation of the W particles reached several percent, indicating an extremely strong particle-matrix bonding. Last, the failure mechanisms of the materials were investigated, with the matrix behavior governing the fatigue failure, and particle-matrix decohesion dominating in the static loading at higher loads.
Permanent Link: https://hdl.handle.net/11104/0350109