4. Special case of creep in dispersoid alloys

4.1 Effect of dispersoids on creep strength

Increased creep resistance can be achieved by the presence of a finely dispersed second phase in a matrix: these dispersoids act as obstacles to the propagation of dislocations. The second phase is composed of :

• very fine ceramic particles, generally oxides ranging in size from 10 nm to a few hundred nanometres;

• metal precipitates.

Creep speed is several orders of magnitude lower than it would be without dispersoids. It depends on the size of the particles and the average distance between them. The smaller the distance between particles, the greater the creep resistance.

Creep mechanisms in nickel-base...