Influence of Gd content on the room temperature mechanical properties of Gd-doped ceria

High-density ceramics of ceria doped with 0, 3, 5, 10, 15 and 20 mol.% Gd and with grain sizes exceeding 1.5 μm were investigated by nanoindentation. The deduced elastic moduli are independent of Gd content and remain close to the value reported for bulk ceramics (210 ± 5% GPa). All ceramics exhibit transient creep with displacement proportional to the 1/3 power of the time. For 0.05 < x < 0.2, the derived creep magnitude parameter decreases linearly with increasing Gd content. These results strongly suggest that defect rearrangement influences the measurements.