How does long-range order affect creep of alloys?

The ‘strength’ of ordering in an intermetallic is measured by the ordering energy; ways of measuring this quantity are reviewed. The influence of ordering energy on the creep resistance of an intermetallic is examined; the slowing down of self-diffusion when long-range order is established is one possible source of enhanced creep resistance, the effect of a high ordering energy in slowing down ‘viscous’ motion of dislocations in a slip plane is another. In this connection, the available published evidence is outlined.