NiAl-25%Cr合金的高温蠕变行为

High-temperature creep behavior of NiAl-25%Cr alloy

研究挤压NiAl-25Cr合金在1073～1123K温度区间的蠕变行为。结果表明：在实验温度区域内，挤压NiAl-25Cr合金表现出两种明显不同的蠕变机制；在低温区域中，由位错的滑移和攀移控制蠕变变形过程；而在高温区域中，位错粘滞滑移控制蠕变变形过程。在研究蠕变的温度范围内，合金的蠕变表观激活能高于Ni的晶格自扩散能，这可以解释为在蠕变瞬时变形过程中，第二相粒子沿着基体相运动的结果，第二相粒子可能是γ-Ni3Al相或α-Cr相。

The creep behavior and mechanisms of extruded NiAl-25Cr alloy at elevated temperatures were investigated. The results of the analysis of the creep data in the temperature range of 1 073 -1 123 K reveals two distinct regions of creep behavior in this material. At lower temperature, the creep characteristics are consistent with a structure controlled creep process where some form of dislocation climb controls the creep deformation. At higher temperature, the creep characteristics are consistent with mobility-controlled deformation where viscous glide of dislocations controls the creep. The apparent activation energies determined for creep in both regions exceed by a considerable amount, the value for lattice self-diffusion in Ni. This can be explained in terms of the simultaneous deformation of second phase particles along with the Ni matrix during creep, The second phase most likely deforming along with the Ni matrix is the γ-Ni3 Al and α-Cr phase.