The microstructures before and after creep were also analyzed by SEM and TEM.The tensile creep behavior and mechanisms of directionally solidified（DS） NiAl-Cr（Mo）-W/Nb alloy were investigated in the temperature range of 1 223-1 373 K.The results show that the transverse microstructure of DS NiAl-Cr（Mo）-W/Nb alloy is typically eutectic cell of NiAl matrix and Cr（Mo） phase.The lamellar Cr（Mo） phase of the longitudinal microstructure is arranged along the direction of the directional solidification.At the present experiment,all of the creep curves of DS NiAl-Cr（Mo）-W/Nb alloy have the similar shape,i.e.shorter primary creep,longer steady state creep stage and higher creep strain.The creep strains are 15%-28%.The creep deformation mechanism is probably controlled by high temperature diffusion and dislocation creep.The creep fracture of this alloy is controlled by formation and propagation of the cracks at the phase boundaries,and the creep fracture mode is debonding along the phase boundary.
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