Stable Storage of Helium in Nanoscale Platelets at Semicoherent Interfaces

He implanted into metals precipitates into nanoscale bubbles that may later grow into voids, degrading the properties of engineering alloys. Using multiscale modeling, we show that a different class of He precipitates may form at semicoherent interfaces: nanoscale platelets. These platelets grow by wetting high-energy interface regions, remain stable under irradiation, and reduce He-induced swelling. Stable storage of He at interfaces may impart unprecedented He resistance to future structural materials.

Figure 1

Stages of He introduction into MDIs at Cu-Nb interfaces.

Figure 2

Two growth modes of He-vacancy clusters at a MDI: parallel to the interface (a)–(c); normal to the interface (c)–(e). Top row: edge-on view of Cu-Nb interface. Bottom row: in-plane view of interface Cu terminal plane.

Figure 3

Location dependence of ${\gamma }_{\mathrm{CuNb}}$ ($\mathrm{J}/{\mathrm{m}}^2$), looking normal to the interface plane. Patches of highest energy coincide with MDIs.

Figure 4

The dependence of $\frac{\partial E_s}{\partial V}$ on $V$. The insets illustrate a spherical cap model of He cluster growth.

Figure 5

$\dot{V}(V)$ for an 18-atom He cluster at a Cu-Nb interface and in perfect fcc Cu.