Residual stress, strain and faults in nanocrystalline palladium and copper

Nanocrystalline Pd and Cu, prepared by inert-gas condensation and warm compaction, were studied using X-ray diffraction techniques. A sample of Cu with submicrometer grain size produced by severe plastic deformation was also examined. The Warren-Averbach technique was used to separate the line broadening due to grain size, t.m.s. strain and faults. Peak shifts and asymmetry were used to determine the long-range surface stresses, stacking-fault probability and twin probability. Young's modulus for a Pd sample was determined by an ultrasonic technique and compared with the coarse-grained, fully dense value.