Internal friction peak due to hydrogen in copper

Copper loaded with 5 at ppm hydrogen exhibits an internal friction relaxation peak at 150 K (period of the alternative stress: 2 s). This peak, called PH, can be interpreted as a consequence of the interaction between dislocations and hydrogen atoms and can be described by means of a thermomechanical break-away model. The main features of PH are discussed in connection with cold-work ratio, hydrogen content (in the range 0 to 5 × 10−6), strain amplitude (in the range 10−5 to 10−4), and conditions of growth and annealing.