Anomalous behaviour of the elasticity modulus in argon-irradiated pure copper

Mechanical spectroscopy over the temperature range 300-1130K has been used to study damping and elastic shear modulus modification in pure copper induced by pulsed argon ion implantation. An anomaly in the variation of the shear modulus with increasing temperature occurred in the form of an abrupt jump to a higher value at 840K. A corresponding abrupt decrease was observed during temperature run-down. The effect decreases with time and disappears completely after 1 week. (UK)