The nature of lead–quasicrystal interfaces and its effect on the melting behaviour of lead nanoparticles embedded in quasicrystalline matrices

Nanoparticles of lead were embedded in Al–Cu–Fe icosahedral matrix by rapid solidification. The embedded particles showed definite orientation relationship with the matrix and the interface, facetted on the major symmetry planes of the matrix, showed coherency. Annealing treatments at 600 and 800°C showed that this particle–matrix interface is unstable. The coherency at this interface is supported by the phason strains formed on rapid quenching. This coherency breaks down on annealing in the stability region of the icosahedral phase, leading to a lowering in the melting temperature of the lead particles.