Fabrication and performance of Al/Cu hybrid mandrel for NIF ignition hohlraum

By comparing the chemical component and machined performance of two kinds of 1100 Al rod, the higher purity one is chosen for Al mandrel. Al mandrel is prepared by diamond turning machine with a surface roughness less than 20 nm (RMS) and Al/Cu hybrid mandrel is explored by depositing a 5 m thick copper layer on Al mandrel via magnetron sputtering deposition. The surface roughness, thickness uniformity and crystallinity of Cu film are analyzed by white light interferometer, XRD. The results show that the prepared Cu film with surface roughness less than 30 nm (RMS), thickness uniformity more than 95%, and cylindricity less than 1 m appears (111) preferential orientation growth. The interfacial bonding strength between Cu film and substrate is strong enough for depositing 11 m thick hohlraum wall containing depleted uranium (DU).