Anelasticity study on interfaces of nanocrystalline Au and nanoporous Au

The grain boundary region and pore play an essential role in nanostructured materials. In the present study, nanoporous ( np-) Au prepared by dealloying (DA np-Au) is studied by means of the anelasticity measurement referring to the nanocrystalline ( n-) Au prepared by the gas-deposition method (GD n-Au). In GD n-Au >0.99 (the subscript, >0.99, denotes the relative density of the specimen referring to the bulk density), the linear increase in the internal friction above 200 K ( Q > 200 K − 1 ) and a broad peak at about 100 K ( P L) are observed. In GD n-Au 0.81 containing nanopores, broad peaks at about 220 K ( P H1) and 260 K ( P H2) as well as P L and Q > 200 K − 1 are observed. In DA np-Au 0.4, P L, P H2 and no Q > 200 K − 1 are observed. Densification of DA np-Au 0.4 by pressing causes a significant increase in both P H1 and P H2, and annealing at 360 K cancels the effect of pressing. These results are discussed in the light of the characteristic grain boundary properties in nanostructured materials.