Microstructures of Pd_47.5Ag_47.5La₅ Alloy Studied by Transmission Electron Microscopy

Abstract

Microstructures of Pd_47.5Ag_47.5La₅ alloy produced by three types of procedure methods, i.e., casting, rapid quenching and rolling, were examined by transmission electron microscopy (TEM). The Pd-Ag-La alloy in as-quenched and subsequent cold-rolled states has a finely mixed non-equilibrium structure consisting of a face-centered cubic (fcc) and LaNi₃-type phases and the structural feature is independent of the two procedure methods. The grain size and the volume fraction of the fcc phase are measured to be about 100 nm and 72%, respectively. The two phases dispersed homogeneously over the whole specimen. The Pd-Ag-La alloy with such a finely mixed structure is attractive for a hydrogen permeative material.