The deformation and fracture of a PWA 1472single crystal oriented in a soft orientation were studied byanalyzing the evolution of slip bands and detailed fractography oftensile specimens tested at low (l0~ (-4)/s) and high (1.0/s) strainrates at room temperature. The results of this study indicated thatthe slip did not start on the system with the highest Schmid factor.This yielding anisotropy has been attributed to the deformation ofthe #gamma#'-Ni_3Al precipitates. The plastic deformation washeterogeneous and occurred by the propagation of a Luders band.Cleavage fracture occurred along the kink bands within a coarseshear band that developed after the activation of the secondary slipsystem. An increase in the strain rate did not affect the yieldstrength significantly, but it enhanced the deformation localization,and hence, decreased the ductility and increased the percentage ofthe cleavage facets. The effect of strain rate is discussed in termsof cross-slip processes.
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