Fabrication of W–1 wt.% TiC composites by spark plasma sintering

Tungsten-Based Composites for Nuclear Fusion Applications

“…Pure W fractures via the intergranular mode due to its weak grain boundaries, indicating that the addition of TiC strengthens the grain boundaries. The average grain size was 3 μm, lower than the grain size of pure W, which is 10 μm [13].…”

“…In the chemical process, tungsten hexachloride serves as the raw material, ethyl alcohol as a solvent, lactic acid as a complexing agent, hydrazine hydrate as a reducing agent, 2,2-dipyridyl as a stabilizer, and ammonia water as a pH controller. The reduction process is carried out in an H 2 atmosphere to avoid oxidation; after the reduction step, SPS is carried out to produce a bulk composite [13]. The preparation of ODS-W composites by another wet chemical process, i.e., the reaction of a W precursor with praseodymium salt in water at room temperature, has also been reported [26].…”

“…The addition of WC in W produced a composite with an increased hardness level, and the hardness values follow the WC, i.e., the hardness increases with an increase in the WC content, due to the high hardness of WC [23]. The hardness of TiC/W (471 Hv), developed by chemical reduction, was also found to be greater than that of pure W [13]. Similar behavior was noted by Kurishita et al when they prepared 0.25-0.8wt%TiC/W through mechanical alloying and HIP [5].…”

“…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].…”

“…As compared to other high-temperature applications, which require good physical and mechanical properties such as high thermal conductivity, good thermal shock resistance and high-temperature strength, toughness and stiffness [12], fusion reactors impose very complex requirements on plasma-facing materials (PFMs) [1]. While PFMs are assumed to be able to sustain high mechanical, thermal and magnetic loads for prolonged periods of time [8], irradiation effects are particularly important in plasma-facing components [13]. Transmutation and ballistic damage, which alter the composition and microstructure of materials due to the interaction between the materials and the high-energy neutron flux (~14 MeV), reduce the mechanical properties of PFMs.…”