Abstract
? 2022 Elsevier B.V.To improve the service performance of Cu/W plasma-facing components (PFCs), the influence of the Cu/W interfacial structure on the resistance against harmful He atoms, including the He weakening effect and He atom intrusion, was investigated using density functional theory (DFT) calculations. The Cu(100)/W(100), Cu(110)/W(110), and Cu(111)/W(111) were selected as the representative Cu/W interfacial structures. The results show that He atom intrusion at the Cu/W interface weakens the interfacial Cu–W ionic bonding strength and the covalent bonding strength simultaneously, causing a decrease in the Cu/W interface bonding property (He weakening effect). The Cu(111)/W(111) interfacial structure shows the largest resistance to the He weakening effect owing to the minimal reduction of the interfacial work of adhesion ~0.45 J/m2; this is attributed to the lesser weakening degree of the Cu–W ionic bonding strength. Moreover, when He atoms diffuse along the Cu/W interface, the interactions between the He atoms at the saddle point and the surrounding Cu and W atoms on the Cu(111)/W(111) interfacial structure are the strongest. The resulting highest energy barrier of ~6.84 eV and the resulting low diffusion coefficient indicate that the Cu(111)/W(111) interfacial structure also has the strongest hindrance capacity against He atom intrusion. Therefore, Cu(111)/W(111) is the most promising Cu/W interfacial structure, which can significantly improve the service performance of the Cu/W PFC.
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