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研究了钕对NiAl-28Cr-5.5 Mo-0.5 Hf共晶合金显微组织及高温流变行为的影响。结果表明:NiAl-28Cr-5.5 Mo-0.5 Hf基体合金是由黑色的Ni Al相和灰白色的Cr(Mo)相组成的共晶组织,在相界处聚集有白色的Ni2Al Hf(Heusler)相,加入稀土钕可细化组织;Ni Al-28Cr-5.5 Mo-0.5 Hf(wNd=0.05%)合金在较高的应变速率(ε.=1.94×10-2s-1和.ε=1.94×10-3s-1)下,含稀土合金的流变应力大于不含稀土合金的流变应力,而在低应变速率(.ε=1.94×10-4s-1)下,这种强化现象消失。幂指数规律和温度补偿的幂指数规律可以很好地描述各种合金的高温压缩流变行为。加入稀土可降低合金的应力指数和变形激活能,这是因为稀土偏聚在相界上,致使相界上的空位浓度发生变化。
The effect of neodymium on the microstructure and high temperature rheological behavior of NiAl-28Cr-5.5 Mo-0.5 Hf eutectic alloy was studied. The results show that NiAl-28Cr-5.5Mo-0.5Hf matrix alloy is a eutectic structure composed of black NiAl phase and off-white Cr (Mo) phase, white Ni2Al Hf (Heusler) The microstructures of NiAl-28Cr-5.5Mo-0.5Hf (wNd = 0.05%) alloy were investigated at higher strain rates (ε = 1.94 × 10-2s-1 and ε = 1.94 × 10- 3s-1), the rheological stress of the rare earth-containing alloys is larger than that of the rare earth-free alloys, but disappears at the low strain rate (ε = 1.94 × 10-4s-1). The exponential law and power exponent law of temperature compensation can well describe the high temperature compression rheological behavior of various alloys. Adding rare earth can reduce the stress index and deformation activation energy, which is due to the segregation of rare earth in the phase boundary, resulting in the phase boundary of the vacancy concentration changes.