FGH96镍基粉末高温合金氧化物夹杂的计算机断层扫描研究

利用计算机断层扫描技术（computed tomography，CT）研究了FGH96镍基粉末高温合金内部Al₂O₃、SiO₂及莫来石三种氧化物夹杂对不同工艺（热等静压工艺、热等静压+热挤压+等温锻造工艺及热等静压+等温锻造工艺）的敏感程度。结果表明:热等静压+等温锻造工艺能显著减小Al₂O₃夹杂物的尺寸和其在合金中的含量，采用热等静压+热挤压+等温锻造工艺最能有效减少SiO₂夹杂物在合金中的含量，而莫来石夹杂对热等静压+热挤压+等温锻造工艺和热等静压+等温锻造工艺均较为敏感，且两种工艺对莫来石夹杂的作用效果类似。夹杂物在实际盘件中呈油饼状，极大地恶化了合金低周疲劳性能，且夹杂物越接近试样表面，试样的低周疲劳性能恶化越显著。热等静压+等温锻造工艺对减小三种夹杂的尺寸均有良好效果，这为人们选取合适工艺消除合金中氧化物夹杂提供了重要参考。

Study on oxide inclusions of nickel-based P/M superalloy FHG96 by computed tomography technology

The sensitivity of oxide inclusions (Al₂O₃, SiO₂, and mullite) in nickel-based powder metallurgy (P/M) superalloy (FGH96) to different processing technology was studied by computed tomography (CT) technology. The results show that, the process of hot isostatic pressing + isothermal forging can significantly reduce the Al₂O₃ inclusion size and decrease the content of Al₂O₃ inclusion in FGH96 alloy; the process of hot isostatic pressing + hot extrusion + isothermal forging can effectively reduce the content of SiO₂ inclusion in the alloy; the mullite inclusions are sensitive to both the process of hot isostatic pressing + hot extrusion + isothermal forging and the process of hot isostatic pressing + isothermal forging, and the effects of the two processes are similar. The inclusions in the actual disc show the oil cake shaped, which greatly deteriorates the low cycle fatigue properties of the alloy. The closer the inclusions are to the sample surface, the more obvious the deterioration of low cycle fatigue properties is. Overall, the process of hot isostatic pressing + isothermal forging shows the good effect on reducing the inclusion size, providing an important reference to eliminate the influence of inclusions in alloys by the appropriate process.