HIGH TEMPERATURE CREEP OF A CU-16 AT PERCENT AL ALLOY

The creep of a Cu-16 at.% Al alloy in the temperature range of 670-1100°K has been investigated by the isothermal tests technique. Two dislocation mechanisms operating in paralell were observed in the given temperature range. In the region of lower temperatures ( 104 T {greater-than or approximate} 11.5) the apparent activation energy Qr1 depends linearly on stress. The value of Q01 corresponding to the stress equal zero is close to the expected activation enthalpy of lattice self-diffusion of copper in the Cu-16 at.% Al solid solution. The stress dependence of minimum creep rate can be described by the power function of the σn type, where n = 6.25. The results for region 1 can be correlated with the model of nonconservative motion of jogs on screw dislocations dependent on lattice self-diffusion. In the region of higher temperatures (region 2) the mechanism dominates characterized by the activation energy that is higher than the expected value of the activation enthalpy of lattice self-diffusion of any component of the investigated solid solution. The stress dependence of creep rate can be described by the power function of σn type, where n = 5.40. The dislocation mechanism dominating in region 2 was not identified. © 1969.