On the threshold stress for dislocation creep in particle strengthened alloys

Abstract Current models describing dislocations by-passing particles by climb do not satisfactorily account for the creep deformation of alloys containing high particle volume fractions such as nickel-base superalloys. An alternative approach involving cooperative climb over groups of particles leads to a resistance to deformation, rather than a threshold stress, that is insensitive to the particle size but which depends strongly on applied stress. Detailed calculations have been carried out for the nickel-base superalloy IN738LC and these are in close agreement with measurements of the friction stress. The theoretical conclusions are generally compatible with the creep behaviour of nickel-base superalloys.

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