W和Ta对新型镍基粉末高温合金显微组织的影响

Effect of W and Ta on microstructure of a new type nickel-base P/M superalloy

采用相同的粉末冶金工艺与热处理方法设计3种W和Ta含量不同的合金,利用金相显微镜(OM)、扫描电镜(SEM)、场发射扫描电镜(FE-SEM)、X射线衍射仪(XRD)等多种研究手段,研究W和Ta元素对新型镍基粉末高温合金显微组织的影响。结果表明:改变W和Ta含量对合金晶粒组织和MC型碳化物的析出没有明显影响;随着合金中Ta含量的减少和W含量的增加,γ/γ′相错配度逐渐减小;随着合金中Ta含量和γ/γ′相错配度的增加,γ′相含量和尺寸均增加,二次γ′相粗化长大和达到分裂的时间缩短,尺寸分布越来越不均匀。

The same powder metallurgy technology and heat treatment method were used to design three alloys with different W and Ta contents.The effects of W and Ta on the microstructure of new type nickel-based P/M superalloys were studied by means of metallographic microscopy(OM),scanning electron microscopy(SEM),field emission scanning electron microscopy(FE-SEM),X-ray diffraction(XRD)and other methods.The results show that the change of W and Ta content has no significant effect on the grain structure and the precipitation of MC carbide.With the decrease of Ta content and the increase of W content in the alloy,theγ/γ′phase mismatch gradually decreases.With the increase of Ta content andγ/γ′phase mismatch,the content and size ofγ′phase increase,the time for the secondaryγ′phase coarsening to grow up and the time to reach the split are shortened,and the size distribution becomes more and more uneven.