Ahatraet-Five polycrystalline nickel-molybdenum single-phase alloys (up to 10 at.% MO) and pure nickel (INCO 270) were tested in compression at two temperatures. The molybdenum solutes contribute not only an additive friction stress, but also a multipii~tive effect on the seen-havening rate. This muitipli~tive effect is interpreted in terms of an infiuence of mobiie solutes on the disi~tion/~sl~tion interaction strength. Solute mobility was evidenced by the occurrence of static strain aging and of a strain-rate sensitivity that has a negative contribution. The total rate sensitivity, however, remained positive and jerky flow was not observed.
RhnCNous avons test& en compression a deux temperatures cinq aliiages polycristallins monophases de nickel et de moiybdene tjusqu'a 10 at.% MO) et du nickel pm (INCO 270). Les atomes de moiybdene en solution provoquent une au~~~tion de la contrainte de friction, mais ils multiplient aussi la vitesse de durcissement. Nous interpr&ons at &et muitipiicatif par une influence des atomes de solute mobiles sur la force de i'interaction dislocation/dislocation. La mobiiid du solute ttait mise m evidence par l'existence d'un vieiiiissement statique et d'une sensibiliti a la v&se de deformation dont la contribution Ctait negative. La sensibilite totaie a la vitcsse restait toutefois positive et I'on n'observait pas d'ircouiement saccade.