Speaker
Description
Tungsten (W) is considered the optimal choice for plasma-facing components (PFCs) in fusion devices due to its high melting point, excellent mechanical properties, and minimal erosion rate. However, studies have shown that W undergoes extreme morphological change when it is bombarded by a high fluence of low-energy ions from helium (He) and deuterium (D) plasmas. To maintain W properties, its alloys—tungsten heavy alloys (W-HA), (90$\%$W-6$\%$Ni-4$\%$Cu), and tungsten-tantalum (W-10$\%$Ta) were investigated as PFCs. The microstructural analysis of He and D ion implanted W and its alloys was conducted using synchrotron grazing incidence X-ray diffraction (GIXRD) and X-ray reflection (GIXRR) techniques at the Canadian Light Source (CLS). The analysis was performed at different grazing incidence angles, 0.5$^{\circ}$, 1$^{\circ}$, 3$^{\circ}$, 5$^{\circ}$ and 7$^{\circ}$ to study near-surface defects. The implantation results unmistakably show that He$^+$ ions inflict significantly more near-surface strain, peak broadening, and distortion than D$^+$ ions, especially up to a depth of 120 nm. At a depth of 1000 nm, $\mathrm{D^+}$ implanted pure-W exhibits a severely deformed (110) GIXRD diffraction peak. W-Ta and W-Ni-Cu alloys did not exhibit (110) peak distortion. The GIXRR revealed that X-ray reflection is lower from implanted samples than un-implanted, confirming the increased surface roughness in ion-implanted W and W-alloy target materials. The results indicate that the negative effects of He$^+$ and D$^+$ ions can be mitigated by alloying W with suitable components.
| Keyword-1 | Synchrotron GIXRD and GIXRR |
|---|---|
| Keyword-2 | PFC's |
| Keyword-3 | W and W-alloys |
