Influence of Neutron Irradiation at Low Temperature on Internal Friction and Bulk Modulus of Silver

The internal friction and the bulk modulus of silver were studied after irradiation at 25 K with fast neutrons. The Frenkel defects produced by irradiation cause dislocation pinning and a consequent decrease in the Bordoni internal friction peak. With increasing irradiation dose the bulk modulus first increases, reaches a maximum and then decreases below its original value. The behaviour of the modulus with annealing up to room temperature essentially corresponds to that of the residual electrical resistivity after low‐temperature neutron irradiation. A Frenkel defect concentration cFD gives rise to a relative dielastic modulus decrease ΔG/G which was determined to be ΔG/(GcFD) = −33 ± 9.