Fracture behavior of tungsten-based composites exposed to steady-state/transient hydrogen plasma

Abstract

Fracture behavior of tungsten-based composites exposed to steady-state/transient hydrogen plasma. Nuclear Fusion, 60(4), [046029].

Recrystallization-mediated crack initiation in tungsten under simultaneous high-flux hydrogen plasma loads and high-cycle transient heating

“…When the desired cross-section plane was approached within 100 μm, intermittent manual grinding steps and SEM analyses were applied to reach the desired plane with a few micrometers accuracy. Finally, the crosssection surface was polished with a 3 μm diamond suspension and finalized with electro-polishing [10]. By comparing the surface cracks near the indents before and after cross-section preparation, it was confirmed that no artifacts were introduced by the cross-section preparation.…”

“…For the hydrogen plasma in Magnum-PSI, collective TS measurements revealed that the ion temperature is close to the electron temperature [36]. This conclusion was used to calculate the steady-state heat flux using the Bohm sheath theory [10]. Likewise, the ion impact energy to the surface on the center of the plasma beam was calculated to be ∼10 eV.…”

“…Polycrystalline samples (20 × 20 × 3 mm 3 ) were cut from a forged pure tungsten rod fabricated by Plansee R . The samples were prepared with a standard metallographic procedure (described in [10]) and then exposed in the linear plasma generator Magnum-PSI [34], which is sketched in figure 1(a). Typical top-view (i.e.…”

“…For example, it may change the retention and sputtering behavior of tungsten. Regarding the structural integrity of the tungsten PFCs, the surface cracks might propagate deep into the material [10], entailing undesirable consequences. Furthermore, the surface cracking may reduce the steady-state power handling capability of tungsten.…”

Chemical short-range order in derivative Cr–Ta–Ti–V–W high entropy alloys from the first-principles thermodynamic study

“…5,6 These advantages are unfortunately coupled with very low fracture toughness characterized by brittle transgranular and intergranular failure regimes, which severely restrict the useful operating temperature window and create a range of fabrication difficulties. [7][8][9] Strategies such as different alloying elements (e.g. W-Cr, W-Re, W-Ta, W-Ti, W-V) or nanostructure engineered W are being investigated to improve the material processing and working properties to extreme irradiation environments.…”