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Stress relaxation in the polycrystalline Ti–6.5 at% Nb alloy is studied at room temperature with the grain size as a principal variable. It is observed that for a given initial stress level from which stress relaxation at constant strain rate 1.6 × 10−3 s−1 is allowed to start, the relaxation rate depends on the average grain diameter D in the range 67 to 117 μm, while it is independent of D for 612 to 751 μm. In addition, the data obtained are also analysed in terms of a single barrier model of stress relaxation. The intrinsic height of the energy barrier to the movement of relaxing dislocations is found to be 2.34 and 1.32 eV for fine‐grained and coarse‐grained crystals, respectively. This is of the order of magnitude for recovery processes.

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