Effect of structure on the fatigue strength of dispersion-hardened Ni-20%Cr-Al2O3 condensed materials

The effect of the mean free path between particles Lambda and the average g rain size D, and also the duration of cyclic loading N in the range (0.2-5) .10(7) cycles, on the fatigue limit of dispersion-hardened Ni - 20% Cr - Al 2O3 condensed materials is studied on the basis of fatigue curves. With a c orp-clarion coefficient of more than 0.9 these dependences on Lambda(-1/2) and D-1/2 correspond to an equation of the Mott-Stroh type. It is shown tha t particle boundaries affect the cyclic strength of the materials to a grea ter extent than grain boundaries up to a concentration of 1.1%. A change in rite fracture mechanism occurs with a correlation coefficient of less than 0.9.