Tungsten (W) is considered a promising plasma-facing material for protecting the divertor of the ITER (International Thermonuclear Experimental Reactor). The effects on W of transient thermal loads of high energy occurring in a tokamak under operative conditions have been simulated through a single laser pulse delivered by an Nd:YAG laser. Bulk and plasma-sprayed (PS) samples have been submitted to tests and successively examined via SEM (scanning electron microscopy) observations. In both types of materials, the laser pulse induces similar effects: (i) a crater forms in the spot central area; (ii) all around the area, the ejection and the movement of molten metal give rise to a ridge; (iii) in a more external area, the surface shows plates with jagged boundaries and cracks induced by thermal stresses; (iv) the pores present in the original material become preferred ablation sites. However, the affected surface area in PS samples is larger and asymmetric if compared to that of bulk material. Such a difference has been explained by considering how microstructural characteristics influence heat propagation from the irradiated spot, and it was found that grain size and shape play a decisive role.

Montanari, R., Pakhomova, E., Pizzoferrato, R., Richetta, M., Varone, A. (2017). Laser pulse effects on plasma-sprayed and bulk tungsten. METALS, 7(11), 454 [10.3390/met7110454].

Laser pulse effects on plasma-sprayed and bulk tungsten

Montanari, Roberto
;
Pakhomova, Ekaterina;Pizzoferrato, Roberto;Richetta, Maria;Varone, Alessandra
2017-01-01

Abstract

Tungsten (W) is considered a promising plasma-facing material for protecting the divertor of the ITER (International Thermonuclear Experimental Reactor). The effects on W of transient thermal loads of high energy occurring in a tokamak under operative conditions have been simulated through a single laser pulse delivered by an Nd:YAG laser. Bulk and plasma-sprayed (PS) samples have been submitted to tests and successively examined via SEM (scanning electron microscopy) observations. In both types of materials, the laser pulse induces similar effects: (i) a crater forms in the spot central area; (ii) all around the area, the ejection and the movement of molten metal give rise to a ridge; (iii) in a more external area, the surface shows plates with jagged boundaries and cracks induced by thermal stresses; (iv) the pores present in the original material become preferred ablation sites. However, the affected surface area in PS samples is larger and asymmetric if compared to that of bulk material. Such a difference has been explained by considering how microstructural characteristics influence heat propagation from the irradiated spot, and it was found that grain size and shape play a decisive role.
2017
Pubblicato
Rilevanza internazionale
Articolo
Esperti anonimi
Settore ING-IND/21 - METALLURGIA
Settore FIS/01 - FISICA SPERIMENTALE
Settore ING-IND/15 - DISEGNO E METODI DELL'INGEGNERIA INDUSTRIALE
English
Con Impact Factor ISI
Laser; Microstructure; Nuclear fusion reactors; Plasma spraying; Tungsten; Materials Science (all)
http://www.mdpi.com/2075-4701/7/11/454/pdf
Montanari, R., Pakhomova, E., Pizzoferrato, R., Richetta, M., Varone, A. (2017). Laser pulse effects on plasma-sprayed and bulk tungsten. METALS, 7(11), 454 [10.3390/met7110454].
Montanari, R; Pakhomova, E; Pizzoferrato, R; Richetta, M; Varone, A
Articolo su rivista
File in questo prodotto:
File Dimensione Formato  
Laser pulse effects.pdf

accesso aperto

Descrizione: Articolo principale
Licenza: Non specificato
Dimensione 9.21 MB
Formato Adobe PDF
9.21 MB Adobe PDF Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2108/191983
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 14
  • ???jsp.display-item.citation.isi??? 7
social impact