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采用压缩实验研究了在应变速率为 1 94× 10 - 3s- 1 时随着温度的变化不同Y含量对铸造NiAl 2 8Cr 5 5Mo 0 5Hf合金力学性能的影响 ,同时 ,运用扫描电镜 (SEM)及其能谱和X射线衍射 (XRD)方法分析了合金的显微组织。结果表明 ,加入Y后 ,合金的显微组织随Y含量的增加而逐渐得到细化 ,表现为共晶团的数目增多 ,共晶团内的Cr(Mo)纤维层间距减小 ,胞界处的Cr(Mo)棒减小 ;当Y含量达到 0 1% (质量分数 )时 ,在NiAl和Cr(Mo)的相界处形成稀土化合物Ni1 7Y2 和Al3Y ,削弱了界面结合力 ,导致屈服强度和塑性下降。此外 ,压缩实验测得在不同温度下 ,0 0 5 %Y含量的合金的压缩强度和压缩率优于其它Y含量的合金 ,所以适量Y可以改善NiAl 2 8Cr 5 5Mo 0 5Hf从室温到高温的强度和塑性
The effects of different Y contents on the mechanical properties of cast NiAl 2 8Cr 5 5Mo 0 5Hf alloy at different strain rates of 1 94 × 10 -3 s -1 were investigated by means of compression experiments. At the same time, SEM, Its energy spectrum and X-ray diffraction (XRD) analysis of the alloy microstructure. The results show that the microstructure of the alloy is gradually refined with the increase of Y content after addition of Y, showing that the number of eutectic groups increases, the interlaminar Cr (Mo) fiber spacing decreases, Of the Cr (Mo) rod decreases. When the Y content reaches 0 1% (mass fraction), the rare earth compounds Ni1 7Y2 and Al3Y are formed at the phase boundaries of NiAl and Cr (Mo), weakening the interfacial bonding force, And dull plasticity. In addition, the compressive experiment shows that the compressive strength and compressibility of alloys with 0 0 5% Y content are better than those of other Y contents at different temperatures, so proper Y can improve the properties of NiAl 2 8Cr 5 5Mo 0 5Hf from room temperature to high temperature Strength and plasticity