Tensile Deformation Behavior of a Nickel-base Superalloy under Dynamic Loads

摘要

The tensile deformation behavior of a nickel-base superalloy under the dynamic loads was investigated the by the optical microscope, scanning electron microscope and transmission electron microscope. The results shown that the yield strength of the alloy increases with the increasing of strain rate, eapacily at the strain rate higher than 101 s-1. While with the increasing of strain rate, the fracture elongation decreases at first, then increases rapidly and shows a minimum value at the strain rate of 102 s-1. The manner in which the dislocations go through the strengthening phases may be different during the plastic deformation at different strain rates and it is the main reason of the appearance of inflection point in the change of the strength with the strain rate. The obvious increasing of plasticity of the alloy at high strain rate is depended on the deformation twining during the plastic deformation.