Synergistic helium and deuterium blistering in tungsten–tantalum composites

Tungsten-Based Composites for Nuclear Fusion Applications

“…W has unique characteristics, which have increased its value relative to other materials. The properties which confer this valuable status in nuclear engineering include its refractoriness, high melting point, high thermal conductivity, low thermal expansion coefficient, good chemical stability, high heat resistance, high sputtering threshold energy, low sputtering rate, low erosion rate at edge plasma temperatures of less than 40-50 eV, low deuterium/tritium retention rate, low tritium permeability, high moduli of elasticity, good thermal shock resistance, lack of hydride formation and adequate corrosion resistance [12,15,[18][19][20][21][22][23][24][25][26][27][28][29][30]. The use of W is associated with other advantages as well.…”

“…W is also associated with high embrittlement due to irradiation at low temperatures [4,22,24], and the DBTT of W increases with an increase in the radiation level [29]. Low-temperature brittleness imposes restrictions on the application of tungsten as a structural material [25,27,28].…”

“…Some of these techniques involve (i) W-based composites [19], (ii) nanocrystalline W-based materials [1,5,34], (iii) W-X (X=Ta, Re, Mo, V, Ti, etc.) alloys created by powder metallurgy [15,[35][36][37][38][39], (iv) the dispersion of ductile fibers in W by mechanical synthesis [25], (v) the dispersion of ceramic particles of transition metals [13], (vi) the addition of rare-earth oxide particles into W [26], (vii) effective energy dissipation caused by controlled cracking and friction at fiber/matrix interfaces [28], and the utilization of functionally graded materials (FGMs) as an efficient solution to the joining problem of W to copper-based heat sinks [34], (viii) the creation of laminated hybrid composites [18], (ix) the post-processing of W to obtain full densification [21], and (x) the addition of a sintering activator to obtain high density levels [21].…”

DEPENDENCES OF HELIUM RETENTION IN TUNGSTEN AND TANTALUM COATINGS IRRADIATED WITH He+ IONS ON FLUENCE AND TEMPERATURE

“…Tungsten and tantalum are considered [1][2][3][4][5] as the protective plasma-facing materials for components of thermonuclear reactors with magnetic [1,[3][4][5] and inertial plasma confinement [2]. They are proposed to be used both as separate materials (W [1,3,5] and Ta [2,3]) and in form of tungsten-tantalum composites [4] (with 10 and 20 at.% Ta fibers in W matrix) and WTa 5 alloys [5] (with 5 wt.% Ta). One of the ways of production of protective coatings for plasma-facing components (PFC) is the plasma sputtering of tungsten or tantalum onto surfaces of PFC [1,2].…”

Consolidation of W–Ta composites: Hot isostatic pressing and spark and pulse plasma sintering

“…In the present work a dispersion of ductile Ta fibers in a W matrix is studied as an approach to the development of tough armor materials [9]. Milling prior to consolidation has been shown to enhance densification of the refractory W-based materials [10], however this operation is expected to promote alloying of the two metallic elements as well as to fracture the ductile Ta phase, reducing the aspect ratio of the Ta fibers [11]. In the present work prior ball milling was used to nanostructure the W matrix while incorporation of Ta particles was achieved subsequently by turbula mixing.…”