On high creep activation energy for cast NiAl-9Mo eutectic alloy

The stress change-strain transient creep experiment was conducted and the side surface of creep-rupture samples was examined in order to study the apparent creep activation energy for NiAl-9Mo alloy. Most of the recoverable strain is established and the strain rate decreases sharply during the initial deformation after unloading the major stress. The magnitude of the recoverable deformation increases only slightly and the strain rate changes slowly during the following course. The relationship between recoverable strain rate and relax time during the relative steady-state stage is fitted in the equation ɛ˙r=Atm (A=1.294E−4, m=−0.450). The backflow process is temperature dependent and is controlled by the flow behavior of the matrix material. The apparent creep activation energy under constant stress is a combination of the activation energy for creep flow of the matrix and that for the damage process at the interface.